Undescribed sesquiterpenoids with NO production inhibitory activity from oleo-gum resin of Commiphora myrrha

Six undescribed cadinane sesquiterpenoids (1-6), two undescribed guaiane sesquiterpenoids (7-8), and an undescribed germacrane sesquiterpenoid (9) were isolated from the oleo-gum resin of Commiphora myrrha. Their structures were determined by the analysis of 1D/2D NMR and HRESIMS data, as well as quantum chemical ECD and NMR calculations. All the sesquiterpenoids were evaluated for their NO production inhibitory activity in LPS-stimulated RAW 264.7 mouse monocyte-macrophages. The results revealed that commiphone A (1) and commipholide D (7) exhibited significant inhibitory effect on NO generation with IC50 values of 18.6 ± 2.0 and 37.5 ± 1.5 μM, respectively. Furthermore, 1 and 7 dose-dependently inhibited the mRNA expression of inflammatory cytokines IL-1β, IL-6 and TNF-α induced by LPS in the RAW264.7 cells, indicating that 1 and 7 possess potent anti-inflammatory activity in vitro.

Identification and characterization of organic and glycosidic acids in the crude resin glycoside fraction of Ipomoea lacunosa seeds

Resin glycosides are commonly found in plants belonging to the Convolvulaceae family. Ipomoea lacunosa L. (Convolvulaceae) is an herbaceous vine native to the United States. The resin glycosides of this plant have not been studied in detail. In this study, the components of the crude resin glycoside fraction extracted from the seeds of I. lacunosa are characterized. Alkaline hydrolysis of the crude resin glycoside fraction obtained from methanolic extract of the seeds yielded three organic acids, namely, 2S-methylbutyric, (E)-2-methylbut-2-enoic, and 2R-methyl-3R-hydroxybutyric acids, and a glycosidic acid fraction. Acidic hydrolysis of the glycosidic acid fraction yielded hydroxyl fatty acid components, including 7S-hydroxydecanoic, 11S-hydroxytetradecanoic, 11S-hydroxyhexadecanoic, 3S,11S-dihydroxytetradecanoic, 3S,11S-dihydroxyhexadecanoic, and 3S,12S-dihydroxyhexadecanoic acids, as well as monosaccharide components, including d-glucose, d-quinovose, d-fucose, and l-rhamnose. Trimethylsilyldiazomethane-hexane treatment of the glycosidic acid fraction further yielded eleven previously undescribed glycosidic acid methyl esters and two known glycosidic acid methyl esters. The structures of the obtained compounds were characterized using various spectral techniques. Four of the undescribed compounds were hexaglycosides, five were heptaglycosides, and two were octaglycosides. The aglycone of these compounds was either methyl 11S-hydroxytetradecanoate, methyl 3S,11S-dihydroxytetradecanoate, or methyl 3S,11S-dihydroxyhexadecanoate. Among the undescribed compounds identified, eight contained novel glycans, and three were rare bisdesmosides with sugar linkages at the C-3 and C-11 positions of methyl 3S,11S-dihydroxytetradecanoate.

Recovery and separation of glycyrrhizic acid from Natural Deep Eutectic Solvent (NADES) extract by macroporous resin: adsorption kinetics and isotherm studies

Natural Deep Eutectic Solvents (NADESs) have emerged as a green and sustainable alternative to conventional organic solvents to extract bioactive compounds. However, the recovery of bioactive compounds from the NADES extracts is challenging, restricting their large-scale applications. The present work investigated the recovery of glycyrrhizic acid (GA) from choline-chloride/lactic acid NADES extract using macroporous resins. GA possesses a wide spectrum of biological activities, and it is extracted from the well-known herb Glycyrrhiza glabra. During resin screening, DIAIONTM SP700 showed high adsorption and desorption capacities. The adsorption kinetics study demonstrated that the adsorption of GA on SP700 followed Pseudo First-order kinetic model. Moreover, the adsorption behaviors were elucidated by the Freundlich isotherm using a correlation coefficient based on a static adsorption study at different temperatures and pH. Furthermore, the thermodynamic parameters, for instance, the change of Gibbs free energy (ΔG*), entropy (ΔS*), and enthalpy (ΔH*), showed that the adsorption process was spontaneous, favorable and exothermic. In addition, the sample after macroporous resin treatment, which is enriched with GA exhibited good anticancer potential analyzed by SRB assay. The regenerated NADES solvent was recycled twice, keeping more than 90% extraction efficiency, indicating good reusability of NADES in the GA extraction process by using macroporous resin.

Stytontriterpenes A-C, three unusual oleanane-derived triterpenoids from the resin of Styrax tonkinensis as potential immunosuppressive agents in atherosclerosis

Three unusual oleanane-derived triterpenoids, stytontriterpenes A-C (1-3), were isolated from the resin of Styrax tonkinensis together with an oleanane-lactone (stytontriterpene D, 4). Their structures and absolute configurations were characterised using a combination of spectroscopic analysis, electronic circular dichroism, and theoretical calculations. 1 and 2 belong to nor-oleanane with rare spiro D/E rings and 3 contains one infrequent C32 scaffold. 1 considerably suppressed the number of adhered leukemic monocytes (THP-1) to human umbilical vein endothelial cells and attenuated the upregulations of mRNA and protein levels of intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 at 5 μM, suggesting that 1 might be a promising anti-vascular inflammatory chemical for atherosclerosis therapy. Plausible biosynthetic pathways for 1-4 are also proposed.

TLC and HPTLC-APCI-MS for the rapid discrimination of plant resins frequently used for lacquers and varnishes by artists and conservators

INTRODUCTION

Depending on their terpenoid and phenolic constituents plant resins can be classified as diterpenoid, triterpenoid or phenolic resins; thereby the profile of diterpenes and triterpenes is considered as genus- or even species-specific.

OBJECTIVES

We aimed to develop a simple, rapid, inexpensive, sensitive and specific method for the identification of resin-specific triterpenoid and phenolic compounds in plant resins using (HP)TLC [(high-performance) thin-layer chromatography] combined with APCI-MS (atmospheric pressure chemical ionisation mass spectrometry) and post-chromatographic detection reactions.

METHODS

Twenty resin samples from different plant species were analysed. Different extraction procedures, post-chromatographic detection reagents as well as various sorbents and solvents for planar chromatography were tested. To evaluate the potential of the optimised (HP)TLC-APCI-MS methods, parameter such as limit of detection (LOD) was determined for selected marker compounds.

RESULTS

Our protocol enabled qualitative analyses of chemotaxonomic molecular markers in natural resins such as dammar, mastic, olibanum and benzoin. For the first time, the application of thionyl chloride-stannic chloride reagent for a specific post-chromatographic detection of triterpenes is reported, sometimes even allowing discrimination between isomers based on their characteristic colour sequences. For triterpene acids, triterpene alcohols and phenolic compounds, detection limits of 2-20 ng/TLC zone and a system precision with a relative standard deviation (RSD) in the range of 3.9%-7.0% were achieved by (HP)TLC-APCI-MS. The applicability of the method for the analysis of resin-based varnishes was successfully tested on a mastic-based varnish. Thus, the method we propose is a helpful tool for the discrimination of resins and resin-based varnishes with respect to their botanical origin.

Inhibition of multidrug-resistant MCF-7 breast cancer cells with combinations of clinical drugs and resin glycosides from Operculina hamiltonii

The jalap roots, Operculina hamiltonii D.F. Austin & Staples (Convolvulaceae), are extensively commercialized as a depurative and laxative remedy in traditional medicine of the north and northeast regions of Brazil. The purification by recycling HPLC and structure elucidation of three new acyl sugars or resin glycosides are described here from a commercial product made of powdered roots. Three macrocyclic structures of a tetrasaccharide of (11S)-hydroxyhexadecanoic acid, operculinic acid C (1), the undescribed hamiltonins II and III (3 and 4), in addition to the known batatinoside III (5), presented a diastereoisomeric relationship as one residue of n-dodecanoic acid esterified the oligosaccharide core on a different position in each compound. Furthermore, hamiltonin IV (6) was characterized as an ester-type homodimer of acylated operculinic acid C with the same substitution pattern identified in hamiltonins II (3) and III (4) for each of the dimer subunits. All the isolated resin glycosides did not display any intrinsic cytotoxicity (IC50 > 25 μM). However, a combination of the individual isolated compounds 3-6 (1-50 μM) demonstrated an enhancement of cytotoxic effects with sublethal doses of vinblastine and podophyllotoxin (0.003 μM) in multidrug-resistant breast carcinoma epithelial cells (MCF-7/Vin).

Isolation and structural characterization of eight new resin glycosides, calyhedins XVI-XXIII, from the rhizomes of Calystegia hederacea

Biological effects attributed to resin glycosides, including cytotoxicity against cancer cells and antibacterial, multidrug resistance-modulating, and antiviral activities have been documented. Penta-glycosides composed of calysolic acid A or calyhedic acid A, which are glycosidic acid components of the crude resin glycoside fraction of Calystegia hederacea, have not yet been isolated from this plant. In this study, eight new resin glycosides, termed calyhedins XVI (1)-XXIII (8), were isolated from the rhizomes of C. hederacea. Compounds 1-8 are penta- or hexa-glycosides with macrolactone structures, and their sugar moieties are partially acylated by five organic acids, including 2S-methylbutyric, (E)-2-methylbut-2-enoic, and 2R-methyl-3R-hydroxybutyric acids. Compounds 1-5 are the first identified macrocyclic resin glycosides with five monosaccharides obtained from this plant, and 2 and 4 are the first to be characterized as containing calyhedic acid A as the glycosidic acid component. Compounds 1-8 were of the four following macrolactone types: one with a 22-membered ring (5), another with a 23-membered ring (6-8), the third with a 27-membered ring (1, 3), and the fourth with a 28-membered ring (2, 4). Compounds 2-8 exhibited cytotoxic activity against HL-60 human promyelocytic leukemia cells comparable to that of the positive control, cisplatin.

Design of Cell-Adhesive Shellac Derivatives and Endowment of Photoswitchable Cell-Adhesion Properties

The emergence of new biodegradable cell-adhesion materials is an attractive topic in biomaterial chemistry, particularly for the development of cell incubation scaffolds and drug encapsulation materials used in in situ regenerative therapy. Shellac is a natural resin with unique film-forming properties and high miscibility with various chemicals, in addition to being biodegradable and nontoxic to biological systems. However, since native shellac does not adhere to mammalian cells, there have been no reports of using shellac to develop cell-adhesive biomaterials. In this study, we report on the development of cell-adhesive shellac derivatives through slight chemical modification. Shellac is a mixture of oligoesters that consists of hydroxyl fatty acids and resin acids, and therefore, all oligomers have one carboxylic acid group at the terminal. We discovered that a simple modification of hydrophobic chemical groups, particularly those containing aromatic groups in the ester form, could dramatically improve cell-adhesion properties for mammalian cells. Furthermore, by using photocleavable esters containing aromatic groups, we successfully endowed photoswitchable properties in cell adhesion. Given that shellac is a low-cost, biodegradable, and nontoxic natural resin, the modified shellacs have the potential to become new and attractive biomaterials applicable to in situ regenerative therapy.

Antitumor and Phytochemical Properties of Ferula assa-foetida L. Oleo-Gum-Resin against HT-29 Colorectal Cancer Cells In Vitro and in a Xenograft Mouse Model

Colorectal cancer (CRC) is one of the most frequently occurring tumors. Ferula assa-foetida oleo-gum-resin (OGR) extract is a traditional cooking spice known for its broad spectrum of biological activities such as antifungal, antiparasitic, and anti-inflammatory activities. This study evaluated the antitumor effect of OGR extract against HT-29 colorectal cancer cells. The OGR chemical composition was analyzed using LC-ESI-MS/MS; MTT, clonogenic assays, and a xenograft model were used to measure cytotoxicity, while apoptotic proteins were detected using Western blotting. Phytochemical analysis revealed that the extract was a rich source of isoflavones, xanthones, and other derivatives. In a dose-dependent manner, the OGR extract significantly inhibited colony formation ability and HT-29 cell growth (IC50 was 3.60 ± 0.02 and 10.5 ± 0.1 mg/mL, respectively). On the other hand, the OGR extract significantly induced apoptosis and increased the expression of some pro-death proteins involved in cellular apoptosis including PUMA, BIM, BIK, and BAK. Moreover, in a subcutaneous HT-29 xenograft model, the tumor volume and burden decreased after treatment with the OGR extract (550 ± 32 mm3 and 16.3 ± 3.6, respectively) This study demonstrated that Ferula assa-foetida OGR ethanolic extract has potential antitumor effects against HT-29 CRC cell lines by reducing cell viability and the function of apoptosis. More studies are needed to reveal the underlying mechanisms related to cytotoxicity and apoptosis induction.

Guided discovery of hepatoprotective polyhydroxy cembrane-type diterpenoids from the gum resin of Boswellia carterii by MS/MS molecular networking

Seven previously undescribed polyhydroxy cembrane-type diterpenoids, olibanols A-G (1-7) were obtained from the gum resin of Boswellia carterii by means of MS/MS molecular networking. Compound 2 possessed four hydroxy groups, 1, 3, 4, 5, and 6 had three hydroxy groups, 7 with one hydroxy group, among which 1 and 4 were a pair of epimers with double bond at C-3 and hydroxy at C-8. Structures of these previously undescribed compounds were determined by NMR analysis and ECD calculations. All the polyhydroxy cembrane-type diterpenoids obtained were assayed for their hepatoprotective effects against the anti-tuberculosis drug-induced hepatic damage to the HRZ-induced HepG2 cells. As results indicated, compounds 3, 4, and 6 showed significant hepatoprotective effects against the hepatic damage via the Nrf2 signal pathway, which could be developed as potential hepatoprotective agents against the anti-tuberculosis drug-induced hepatic damage.

From rosin to novel bio-based silicone rubber: a review

Rosin is a characteristic natural renewable resource. In view of the unique hydrogenated phenanthrene ring skeleton structure of rosin, it can be designed and synthesized to modify silicone rubber for improving its mechanical properties, thermal stability, and other properties. In this paper, the research progress of silicone rubber modified by rosin and its derivatives is reviewed, including internal or surface modification of room temperature or high temperature vulcanized silicone rubber. The different chemical modifications and polymerization pathways to obtain bio-based silicone rubber (e.g. rosin-based silicone cross-linking agent, filler compound rosin-based silicone cross-linking agent, rosin-based polymer, and rosin quaternary ammonium salt bifunctional antibacterial coating) are discussed and its research prospect is reviewed. Overall, the present review article will provide a quantitative experimental basis for rosin to produce bio-renewable multifunctional silicone rubber to increase our level of understanding of the behavior of this important class of silicone rubber and other similar bio-based polymers.

Nine pairs of undescribed enantiomers from the resin of Styrax tonkinensis (Pierre) Craib ex Hart with anti-inflammatory activity

Nine pairs of undescribed enantiomers, (±)-styraxoids A-I (1-9), were isolated from the resin of Styrax tonkinensis, and their structures were assigned by spectroscopic and computational methods. Compounds (±)-1 are a pair of degraded lignans, and the remaining compounds (±)-(2-9) are phenylpropanoid skeletons. Compounds (±)-8 and (±)-9 feature a 1,3-dioxolane moiety. The biological evaluation showed that both enantiomers of 1 could inhibit LPS-induced INOS and COX-2 in RAW264.7 cells in a dose-dependent manner.

Five new resin glycosides, calyhedins XI-XV, from Calystegia hederacea

Calystegia hederacea Wall. (Convolvulaceae) is a perennial herbaceous vine that grows widely in India and East Asia. All parts of this plant are used to treat various disorders such as menoxenia and gonorrhea. Four new resin glycosides, calyhedins XI (1)-XIV (4), were isolated from the rhizomes of C. hederacea. A new glycoside, calyhedin XV (5), was isolated from its leaves and stems. Alkaline hydrolysis of 1 and 2 furnished a new glycosidic acid, calyhedic acid G (1a), from 1 and a new acid, calyhedic acid H (2a), from 2 along with 2S-methylbutyric acid and 2R-methyl-3R-hydroxybutyric (2R,3R-nilic) acid. The structures of 1-5, 1a, and 2a were determined using MS and NMR spectral analyses. Compounds 1a and 2a had the same sugar moiety, β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranosyl-(1 → 6)-O-β-D-glucopyranosyl-(1 → 3)-[O-β-D-glucopyranosyl-(1 → 3)-O-α-L-rhamnopyranosyl-(1 → 2)]-O-β-D-glucopyranosyl-(1 → 2)-β-D-fucopyranose, while their aglycones were 11S-dihydroxyhexadecanoic acid and 12S-dihydroxyhexadecanoic acid, respectively. These compounds are the first glycosidic acids, with fucose as the monosaccharide component obtained from the resin glycosides of C. hederacea. Compounds 1-5, comprising either 1a or 2a, were heptaglycosides with macrolactone structures, and their sugar moieties were partially acylated with 5 mol of organic acids comprising 2S-methylbutyric, (E)-2-methylbut-2-enoic, and 2R,3R-nilic acids. Compounds 1 and 5 had 22-membered rings, while 2-4 had 28-membered rings. In addition, 1 and 5 exhibited cytotoxic activity against HL-60 human promyelocytic leukemia cells, comparable to that of the positive control cisplatin.

In-vivo anti-diabetic and anti-hyperlipidemic effects of natural metabolites from resin of Commiphora mukul and their in-silico to in-vitro target fishing

Diabetes mellitus is a rapidly spreading global metabolic disorder that has serious social, health, and economic consequences. Herein, we have evaluated in vivo antidiabetic and antihyperlipidemic effects of myrrhanone-B and myrrhanol-B (isolated from Commiphora mukul Hook). We observed that treatment with myrrhanone-B and myrrhanol-B at a dose of 5 and 10 mg/kg body weight for 21 days significantly improved body weight loss, water consumption, and the concentration of blood glucose level (BGL) in alloxan (120 mg/kg) induced diabetic mice, which indicates that the compounds possess strong anti-diabetic activities. In the biochemical analysis, these compounds improved an abnormal level of total cholesterol (TC), triacylglycerol (TG), and low-density lipoprotein cholesterol (LDL-C) to a normal level and increased the high-density lipoprotein cholesterol level (HDLC). Later, drug target of compounds was predicted through in-silico docking which shows that these compounds nicely fit in the active site of α-glucosidase enzyme and mediates excellent interactions with the catalytic residues, Asp214 and Asp349. The in-silico results were confirmed by in-vitro testing of myrrhanone-B and myrrhanol-B against α-glucosidase where both the compounds exhibited excellent inhibitory potency with IC50 values of 19.50 ± 0.71, and 16.11 ± 0.69 µM, respectively. Furthermore, mechanistic study was conducted to observe their binding mechanism, which reflect that myrrhanol-B has mixed type of inhibition (ki = 12.33 ± 0.030 µM), while myrrhanone-B demonstrates competitive type of inhibition (ki =14.53 ± 0.040 µM).

Phytochemical study of Boswellia dalzielii oleo-gum resin and evaluation of its biological properties

Boswellia dalzielii is a resin-producing tree endemic to West and Central Africa, used by local populations for various medicinal purposes. In this study, B. dalzielii gum resin was analyzed by GC-MS and UHPLC-MS to identify and quantify volatile and non-volatile compounds. Its main volatile constituents were α-pinene (54.9%), followed by α-thujene (4.4%) and α-phellandren-8-ol (4.0%). Pentacyclic triterpenoids such as β-boswellic acids and their derivatives were quantified by UHPLC-MS and their content was shown to reach around 22% of the gum resin. Since some of the volatile and non-volatile compounds identified in this work are known to possess biological effects, the bioactivities of B. dalzielii ethanolic extract, essential oil, as well as fractions of the oil and extract were evaluated. Some of these samples exhibited interesting anti-inflammatory properties, and their antioxidant, anti-ageing and skin-bleaching activities were also tested.

Chios Mastic Gum: Chemical Profile and Pharmacological Properties in Inflammatory Bowel Disease: From the Past to the Future

Chios mastic gum, the product of the tree Pistacia lentiscus var. Chia, has been used for more than 2500 years in traditional Greek medicine for treating several diseases, thanks to the anti-inflammatory and antioxidant properties of its components. Despite the long-time use of mastic in gastroenterology and in particular in chronic-inflammation-associated diseases, to date, the literature lacks reviews regarding this topic. The aim of the present work is to summarize available data on the effects of P. lentiscus on inflammatory bowel disease. A comprehensive review of this topic could drive researchers to conduct future studies aimed at deeply investigating P. lentiscus effects and hypothesizing a mechanism of action. The present review, indeed, schematizes the possible bioactive components of mastic gum. Particular care is given to P. lentiscus var. Chia medicaments' and supplements' chemical compositions and their pharmacological action in inflammatory bowel disease.

Four new resin glycosides, calyhedins VII-X, from the rhizomes of Calystegia hederacea

Four new resin glycosides with macrolactone structures (jalapins), namely, calyhedins VII (1)-X (4), were isolated from the rhizomes of Calystegia hederacea Wall. (Convolvulaceae). The structures of 1-4 were determined based on spectroscopic data. They were classified into three ring types: a 27-membered ring (1), a 22-membered ring (2, 3), and a 23-membered ring (4). Their sugar moieties were partially acylated using five organic acids, including (E)-2-methylbut-2-enoic acid, 2S-methylbutyric acid, and 2 R-methyl-3R-hydroxybutyric acid. Compound 4 was the first genuine resin glycoside with calyhedic acid F as the glycosidic acid component. Additionally, the cytotoxic activities of 1, 2, and 4 towards HL-60 human promyelocytic leukaemia cells were evaluated. All compounds demonstrated almost the same activity as the positive control, cisplatin.

Influence of gamma irradiation on rosin properties and its antimicrobial activity

The main component of rosin natural gum is abietic acid, which has an interesting chemical structure to be studied with the influence of gamma-ray and the antimicrobial activity on the properties of a cheap abundant solid state natural material of rosin. Rosin is exposed to a wide scale of gamma-ray ranges from 0 to 100 kGy. The changes in the properties are tracked by various techniques of FTIR, XRD, TGA, GPC, and SEM. The molecular weight of rosin changes from 370 g/mol to higher and the morphological properties were investigated. The irradiated rosin acid (IRA) at different irradiation doses exploited antimicrobial effect versus Gram-positive and Gram-negative as well. The inhibition zone enhanced from 15 to 33, 14 to 28, 14 to 20, and 9 to 14 mm for Gram-positive and Gram-negative, respectively. Moreover, bioactive behavior for irradiated rosin of 40 kGy recorded the highest antibacterial activity against both types of bacteria. The outcome data of antimicrobial activity are good and confirm that there is a significant effect of irradiation dose on the biocidal activity of rosin.

Identification and characterization of organic and glycosidic acids in the crude resin glycoside fraction from the leaves and stems of Calystegia japonica

The alkaline hydrolysis of the crude resin glycoside fraction from the leaves and stems of the plant Calystegia japonica Choisy (Convolvulaceae) yielded organic acid and glycosidic acid fractions. The organic acid fraction was esterified with p-bromophenacyl bromide to obtain p-bromophenacyl 2R-methyl-3R-hydroxybutyrate (1) and p-bromophenacyl (E)-2-methylbut-2-enoate (2). By treating the glycosidic acid fraction with trimethylsilyldiazomethane-hexane, seven new methyl esters of glycosidic acids, namely calyjaponic acid A methyl ester (3) calyjaponic acid B methyl ester (5), calyjaponic acid C methyl ester (6), calyjaponic acid D methyl ester (7), calyjaponic acid E methyl ester (8), calyjaponic acid F methyl ester (9), and calyjaponic acid G methyl ester (10), were isolated along with one known ester (4). Their structures were characterized based on spectroscopic and chemical analyses. Compounds 3-8 had the same sugar moiety, α-L-rhamnopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 2)-[O-α-L-rhamnopyranosyl-(1 → 6)]-O-β-D-glucopyranose, and the aglycones of 3-8 were methyl 3S,11S-dihydroxyhexadecanoate, methyl 3S,12S-dihydroxyhexadecanoate, methyl 11S-hydroxyhexadecanoate, methyl 11S-hydroxypentadecanoate, methyl 3S,11S-dihydroxypentadecanoate, and methyl 3S,12S-dihydroxypentadecanoate, respectively. Compounds 9 and 10 were derivatives of 3 and 4, respectively, in which the C-6 of the second glucosyl residue was methylated. Compounds 6-8 contained methyl esters of unusual odd-carbon fatty acids as aglycones. The cytotoxicity of the crude resin glycoside fraction and 3 against HL-60 human promyelocytic leukemia cells was evaluated further; both were either weakly active or inactive compared to the positive control, cisplatin.

Terpenoids from Myrrh and Their Cytotoxic Activity against HeLa Cells

The oleo-gum resin of Commiphora myrrha (Nees) Engl. has a long history of medicinal use, although many of its constituents are still unknown. In the present investigation, 34 secondary metabolites were isolated from myrrh resin using different chromatographic techniques (silica flash chromatography, CPC, and preparative HPLC) and their structures were elucidated with NMR spectroscopy, HRESIMS, CD spectroscopy, and ECD calculations. Among the isolated substances are seven sesquiterpenes (1-7), one disesquiterpene (8), and two triterpenes (23, 24), which were hitherto unknown, and numerous substances are described here for the first time for C. myrrha or the genus Commiphora. Furthermore, the effects of selected terpenes on cervix cancer cells (HeLa) were studied in an MTT-based in vitro assay. Three triterpenes were observed to be the most toxic with moderate IC₅₀ values of 60.3 (29), 74.5 (33), and 78.9 µM (26). Due to the different activity of the structurally similar triterpenoids, the impact of different structural elements on the cytotoxic effect could be discussed and linked to the presence of a 1,2,3-trihydroxy substructure in the A ring. The influence on TNF-α dependent expression of the intercellular adhesion molecule 1 (ICAM-1) in human microvascular endothelial cells (HMEC-1) was also tested for 4-6, 9-11, 17, 18, 20, and 27 in vitro, but revealed less than 20% ICAM-1 reduction and, therefore, no significant anti-inflammatory activity.

Synthesis and Structure Revision of Naturally Occurring Homoisoflavane (+)-Dracaeconolide B

Dracaeconolide B (1), a naturally occurring homoisoflavane, was isolated from the red resin of Dracaena cochinchinensis. Efforts have been made to elucidate the exact structure of compound 1 since it was confirmed that dracaeconolide B did not contain a 7-hydroxy-5,8-dimethoxy moiety. The structure of dracaeconolide B was revised by synthesis of three homoisoflavanes containing a 5,6,7-trioxygenated moiety each and analysis by NMR spectroscopy. The revised structure of dracaeconolide B was proposed as 3-(4-hydroxybenzyl)-7-hydroxy-5,6-dimethoxychromane. Noyori's Ru-catalyzed asymmetric transfer hydrogenation was used to synthesize (+)-dracaeconolide B. The absolute configuration of the compound was revised to S based on the results obtained by the electronic circular dichroism calculation. We examined the antiangiogenic activity of (S)- and (R)-dracaeconolide B and of synthetic 5,6,7- and 5,7,8-trioxygenated homoisoflavanes. The results can potentially help in the synthesis of related natural products and support drug discovery to treat neovascular eye diseases.

Frankincense-Myrrh treatment alleviates neuropathic pain via the inhibition of neuroglia activation mediated by the TLR4/MyD88 pathway and TRPV1 signaling

BACKGROUND

Neuroglia are important modulators of neuronal functionality, and thus play an integral role in the pathogenesis and treatment of neuropathic pain (NP). According to traditional Chinese medicine, Frankincense-Myrrh is capable of "activating blood and dissipating blood stasis", and as such these two biological compounds are commonly used to treat NP, however, the mechanisms underlying the efficacy of such treatment are unclear.

PURPOSE

This study aimed to further elucidate the protective effects associated with the Frankincense-Myrrh treatment of NP.

METHODS

A chronic sciatic nerve compression injury (CCI) model of NP was established, after which animals were gavaged with Frankincense, Myrrh, Frankincense-Myrrh, or the positive control drug pregabalin for 14 days. Network pharmacology approaches were used to identify putative pathways and targets associated with the Frankincense-Myrrh-mediated treatment of NP, after which these targets were subjected to in-depth analyses. The impact of TLR4 blockade on NP pathogenesis was assessed by intrathecally administering a TLR4 antagonist (LRU) or the MyD88 homodimerization inhibitory peptide (MIP).

RESULTS

Significant alleviation of thermal and mechanical hypersensitivity in response to Frankincense and Myrrh treatment was observed in NP model mice, while network pharmacology analyses suggested that the pathogenesis of NP may be related to TLR4/MyD88-mediated neuroinflammation. Consistently, Frankincense-Myrrh treatment was found to reduce TLR4, MyD88, and p-p65 expression in spinal dorsal horn neuroglia from treated animals, in addition to inhibiting neuronal TRPV1 and inflammatory factor expression. Intrathecal LRU and MIP delivery were sufficient to alleviate thermal and mechanical hyperalgesia in these CCI model mice, with concomitant reductions in neuronal TRPV1 expression and neuroglial activation in the spinal dorsal horn.

CONCLUSION

These data suggest that Frankincense-Myrrh treatment was sufficient to alleviate NP in part via inhibiting TLR4/MyD88 pathway and TRPV1 signaling activity. Blocking TLR4 and MyD88 activation may thus hold value as a means of treating NP.

[Combination characteristics of frankincense and myrrh and progress and prospect of their combination efficacy and mechanism]

Herbal pair is formed based on the experience summary of doctors' deep understanding and perception of the medicinal nature in long-term clinical practice. It gradually becomes the exquisite structural unit for preparing traditional Chinese medicine(TCM) prescriptions, and often plays a core bridge role in the prescription combination. Frankincense and myrrh are raw resin materials of incense abroad, which are subsequently included as Chinese medicinal herbs and endowed with rich medicinal connotation. With the functions of relaxing Zang-fu organs, activating blood and relieving pain, they have definite clinical efficacy. From the perspective of herbal description and clinical application, this study systematically analyzed the combination of frankincense and myrrh as well as their combination proportion, efficacy characterization, diseases and syndromes, effective components and action mechanism. On this basis, the focus of in-depth research of frankincense-myrrh and the application prospects were proposed, in order to further reveal the potential meditation law of this herbal pair, thus contributing to clinical practice and drug innovation of traditional Chinese medicine, and providing reference for understanding of TCM medicinal nature and research of herbal pairs.

Resin Glycosides from Operculina hamiltonii and Their Synergism with Vinblastine in Cancer Cells

Operculina hamiltonii is a vine native to the north and northeast region of Brazil, where its roots are traded as a depurative and laxative remedy with the name of Brazilian jalap in traditional medicine. Procedures for the isolation, purification by recycling HPLC, and structure elucidation of three undescribed resin glycosides are presented herein. Hamiltonin I (1) represents a macrocyclic structure of a tetrasaccharide of (11S)-hydroxyhexadecanoic acid. Additionally, two acyclic pentasaccharides, named hamiltoniosides I (2) and II (3), were also isolated, which are related structurally to the known compounds 4 and 5, macrocyclic lactone-type batatinosides. The tetrasaccharide core of 1 was diacylated by n-decanoic acid and the unusual n-hexadecanoic acid moiety, while the pentasaccharides 2-5 were esterified by one unit of n-decanoic or n-dodecanoic acid. All the isolated compounds were found to be inactive as cytotoxic agents. However, when they were evaluated (1-25 μM) in combination with a sublethal concentration of the anticancer agent vinblastine (0.003 μM), a significant enhancement of the resultant cytotoxicity was produced, especially for multidrug-resistant breast carcinoma epithelial cells. Such combined synergistic potency may be beneficial for chemotherapy, making resin glycosides potential candidates for drug repurposing of conventional chemotherapeutic drugs to reduce their side effects.

Phytochemical Composition of Commiphora Oleogum Resins and Their Cytotoxicity against Skin Cancer Cells

Oleogum resins of the genus Commiphora have been used in traditional medicines for centuries. More than 200 Commiphora species exhibit highly variable phytochemical compositions. A novel highly selective, sensitive, accurate HPLC-MS/MS method was developed and validated to quantify five characteristic phytosteroids and furanosesquiterpenoids, namely (E)-guggulsterone, (Z)-guggulsterone, curzerenone, furanoeudesma-1,3-diene, and myrrhone. The resulting contents and additionally GC analysis were used to classify and differentiate Commiphora oleogum resins of the species C. myrrha, C. erythraea, C. mukul, C. holtziana, C. confusa, and C. kua, as well as unspecified resins. Interestingly, a Commiphora sample from Ogaden, Ethiopia, comprised 446 ng/mg guggulsterones presumed to be unique to C. mukul from the Indian subcontinent. However, Commiphora from Ogaden differed considerably from C. mukul in respect to guggulsterones isomer’s ratio. Moreover, the cytotoxicity of Commiphora extracts, essential oils, botanical drugs containing Commiphora, and pure compounds against the epidermoid carcinoma A431, malignant melanoma RPMI-7951 and SK-MEL-28 cells was investigated in vitro. Thereby, especially C. mukul extract and C. myrrha essential oil exhibited high cytotoxicity against skin cancer cells with IC₅₀ of 2.9–10.9 µg/mL, but were less toxic to normal keratinocytes. In summary, Commiphora oleogum resins and its phytochemicals warrant further investigation aiming at chemotaxonomical classification as well as application in skin cancer treatment.

Calysepins I-VII, Hexasaccharide Resin Glycosides from Calystegia sepium and Their Cytotoxic Evaluation

Seven new hexasaccharide resin glycosides, named calysepins I-VII (1-7), with 27-membered rings, were obtained from the aerial parts of Calystegia sepium. Their structures with absolute configuration were established on the basis of spectroscopic data interpretation analysis and the use of chemical methods. They were defined as hexasaccharides composed of one d-quinovose, four d-glucose, and one l-rhamnose unit, and their sugar moieties were partially acylated by (2S)-methylbutanoic acid in 1-7 and (2R,3R)-nilic acid in 1-5 and 7, which mainly differed at the positions of acylation. Additionally, calysepin IV (4) exhibited cytotoxicity against A549 cells with an IC₅₀ value of 5.2 μM.

Plant sources, techniques of production and uses of tar: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Throughout history, Humans have always used tar for different purposes such as gluing materials, waterproofing, and conserving wood, but today, it is also used in medicines and cosmetics. Many countries around the world, Norway and Morocco to name a few, obtain tar from endemic trees. In a process of dry distillation, the organic material, endemic trees in this case, is exposed to a high temperature with a restricted amount of oxygen. Eventually, it cracks the large molecules in the matter and turns it into tar.

AIM OF THE REVIEW

This review article sheds light on tar production and the species that have been used in the process. Equal emphasis is placed on its uses, chemical composition, and toxicity.

MATERIALS AND METHODS

Meta-analysis (PRISMA) guidelines have been used to review this article. The review is put together from various articles, theses, documents in "Science Direct", "Hal (Archive ouvert)", "Web of knowledge" without limitation date.

RESULTS

It turns out that tar can be produced by 18 tree taxonomic families, notably Cupressaceae, Pinaceae, and Betulaceae. As for the production techniques, two methods are considered: Per ascensum and Per descensum, which can take different forms. The chemical composition of tar consists of acids, phenols, and aromatic hydrocarbons. The uses of tar have changed over time, while its toxicity is strongly related to its chemical composition.

CONCLUSIONS

The different species used in tar production have been highlighted in this research review. Equal importance has been given to its methods of extraction, uses and its chemical components. We hope that future studies will focus more on these species used to produce tar in other biological activities.

Novel Temperature-Responsive Rosin-Derived Supramolecular Hydrogels Constructed by New Semicircular Aggregates

A highly water-soluble rosin-based surfactant (C₁₄-MPA-Na) was synthesized. Novel temperature-responsive supramolecular hydrogels were further prepared using C₁₄-MPA-Na. The microstructure and the mechanical properties of the hydrogels were investigated. Unexpectedly, instead of the long one-dimensional structure, a new kind of twisted semicircular aggregate was formed in the hydrogels, which was rarely reported. Besides, the hydrogels possessed excellent shear-recovery properties. Upon heating to 40 °C, the hydrogels transformed into viscoelastic solutions, which were constructed by worm-like micelles. By adjusting the temperature, the hydrogels and the viscoelastic solutions could be freely transformed. Nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy were used to further explore the possible self-assembly mechanism of C₁₄-MPA-Na. The curved alkane chain which partially overlapped with rosin's rigid skeleton became stretched when heated to 40 °C. The introduction of the rosin rigid skeleton endowed the supramolecular hydrogels with a novel microstructure and contributed to the development of strategies for the utilization of forest resources.

Commikuanoids A-C: New cycloartane triterpenoids with exploration of carbonic anhydrase-II inhibition from the resins of Commiphora kua by in vitro and in silico molecular docking

Three new cycloartane triterpenoids, commikuanoids A-C (1-3), together with four known compounds 4-7, were isolated from the resin of Commiphora kua. Their structures were confirmed by advanced NMR techniques such as 1D (¹H and ¹³C) and 2D (HMBC, HSQC, COSY, NOESY and NOE) and high-resolution mass spectrometry (HRMS). Five compounds (1-5) were screened for in vitro carbonic anhydrase II (CA II) inhibitory activity. All the tested compounds demonstrated significant activity against CA II with IC₅₀ values ranging from 4.9-19.6 μM. Moreover, the binding pattern of each compound in the binding site of CA-II was predicted through in silico molecular docking approach. It was observed that compounds 2, 4, and 5 binds with the Zn ion present in the active site of CA II, while compounds 1 and 3 mediated hydrogen bonding with Thr199 of CA-II, and all the compounds showed good binding score (> - 5 kcal/mol).

Drought effects on volatile organic compound emissions from Scots pine stems

Tree stems have been identified as sources of volatile organic compounds (VOCs) that play important roles in tree defence and atmospheric chemistry. Yet, we lack understanding on the magnitude and environmental drivers of stem VOC emissions in various forest ecosystems. Due to the increasing importance of extreme drought, we studied drought effects on the VOC emissions from mature Scots pine (Pinus sylvestris L.) stems. We measured monoterpenes, acetone, acetaldehyde and methanol emissions with custom-made stem chambers, online PTR-MS and adsorbent sampling in a drought-prone forest over the hot-dry summer of 2018 and compared the emission rates and dynamics between trees in naturally dry conditions and under long-term irrigation (drought release). The pine stems were significant monoterpene sources. The stem monoterpene emissions potentially originated from resin, based on their similar monoterpene spectra. The emission dynamics of all VOCs followed temperature at a daily scale, but monoterpene and acetaldehyde emission rates decreased nonlinearly with drought over the summer. Despite the dry conditions, large peaks of monoterpene, acetaldehyde and acetone emissions occurred in late summer potentially due to abiotic or biotic stressors. Our results highlight the potential importance of stem emissions in the ecosystem VOC budget, encouraging further studies in diverse environments.

Navigating through chemical space and evolutionary time across the Australian continent in plant genus Eremophila

Eremophila is the largest genus in the plant tribe Myoporeae (Scrophulariaceae) and exhibits incredible morphological diversity across the Australian continent. The Australian Aboriginal Peoples recognize many Eremophila species as important sources of traditional medicine, the most frequently used plant parts being the leaves. Recent phylogenetic studies have revealed complex evolutionary relationships between Eremophila and related genera in the tribe. Unique and structurally diverse metabolites, particularly diterpenoids, are also a feature of plants in this group. To assess the full dimension of the chemical space of the tribe Myoporeae, we investigated the metabolite diversity in a chemo-evolutionary framework applying a combination of molecular phylogenetic and state-of-the-art computational metabolomics tools to build a dataset involving leaf samples from a total of 291 specimens of Eremophila and allied genera. The chemo-evolutionary relationships are expounded into a systematic context by integration of information about leaf morphology (resin and hairiness), environmental factors (pollination and geographical distribution), and medicinal properties (traditional medicinal uses and antibacterial studies), augmenting our understanding of complex interactions in biological systems.

Identification and Capture of Phenolic Compounds from a Rapeseed Meal Protein Isolate Production Process By-Product by Macroporous Resin and Valorization Their Antioxidant Properties

In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis to convert sinapine, and sinapic acid derivatives present in the permeate, to sinapic acid. The adsorption of phenolic compounds was investigated using five macroporous resins, including XAD4, XAD7, XAD16, XAD1180, and HP20. Among them, XAD16 showed the highest total phenolic contents adsorption capacities. The adsorption behavior of phenolic compounds was described by pseudo-second-order and Langmuir models. Moreover, thermodynamics tests demonstrated that the adsorption process of phenolic compounds was exothermic and spontaneous. The highest desorption ratio was obtained with 30% (v/v) and 70% (v/v) ethanol for sinapine and sinapic acid, respectively, with a desorption ratio of 63.19 ± 0.03% and 94.68 ± 0.013%. DPPH and ABTS tests revealed that the antioxidant activity of the hydrolyzed fraction was higher than the non-hydrolyzed fraction and higher than the one of vitamin C. Antioxidant tests demonstrated that these phenolic compounds could be used as natural antioxidants, which can be applied in the food industry.

Characterization of Phenolic Plant Exudates by Nuclear Magnetic Resonance Spectroscopy

The class of plant exudates that contain the phenol functionality, termed phenolics, is defined, surveyed, and characterized by solid-state ¹³C NMR spectroscopy and by solution-state ¹H NMR spectroscopy. Materials in this group are identified by the phenolic ¹³C resonance (from the ipso carbon of ArOH) at δ 145-160 (δ 160-167 for ArOR). The resonance patterns define several subclasses based on the collective similarity of their ¹³C spectra, specifically, aloetics from the genus Aloe, guaiacs from the genus Guaiacum and other eurosid and conifer genera, xanthics from the genus Garcinia, and kinos from the genus Eucalyptus and many other genera. Phenolic exudates often are mixed with terpenoid materials (the building block of exudates known as resins) and carbohydrates (the building block of exudates known as gums) to form hybrid subgroups such as guaiac gums, guaiac resins, and kino resins. There are numerous phenolic exudates not affiliated with any of these groups, both as pure phenolics and as hybrids (phenolic resins, phenolic gum resins, and phenolic waxes).

Configurational Assignment of a Flexible Benzo[g]isochromene Stereodiad from Rubia philippinensis and Inhibition of Soluble Epoxide Hydrolase Activity

A new benzo[g]isochromene possessing a conformationally mobile moiety was identified from Rubia philippinensis. The 2D structure was established utilizing spectrometric and spectroscopic techniques with variable temperatures. The configurational investigation of the flexible moiety was investigated utilizing contemporary NMR-combined computational tools such as DP4, direct J-DP4, and DP4 Plus. The probabilities computed from DP4 Plus analysis, featuring inclusion of an additional geometry optimization process, demonstrated more conclusive probability scores among the analyses used. The configurational assignment was also supported by compositional and molecular orbital analyses. Compound 1 inhibited soluble epoxide hydrolase (IC₅₀ = 0.6 ± 0.01 μM), an enzyme associated with cardiovascular disorders.

BAHD acetyltransferase contributes to wound-induced biosynthesis of oleo-gum resin triterpenes in Boswellia

Triterpenes (30-carbon isoprene compounds) represent a large and highly diverse class of natural products that play various physiological functions in plants. The triterpene biosynthetic enzymes, particularly those catalyzing the late-stage regio-selective modifications are not well characterized. The bark of select Boswellia trees, e.g., B. serrata exudes specialized oleo-gum resin in response to wounding, which is enriched with boswellic acids (BAs), a unique class of C3α-epimeric pentacyclic triterpenes with medicinal properties. The bark possesses a network of resin secretory structures comprised of vertical and horizontal resin canals, and amount of BAs in bark increases considerably in response to wounding. To investigate BA biosynthetic enzymes, we conducted tissue-specific transcriptome profiling and identified a wound-responsive BAHD acetyltransferase (BsAT1) of B. serrata catalyzing the late-stage C3α-O-acetylation reactions in the BA biosynthetic pathway. BsAT1 catalyzed C3α-O-acetylation of αBA, βBA, and 11-keto-βBA in vitro and in planta assays to produce all the major C3α-O-acetyl-BAs (3-acetyl-αBA, 3-acetyl-βBA, and 3-acetyl-11-keto-βBA) found in B. serrata bark and oleo-gum resin. BsAT1 showed strict specificity for BA scaffold, whereas it did not acetylate the more common C3β-epimeric pentacyclic triterpenes. The analysis of steady-state kinetics using various BAs revealed distinct substrate affinity and catalytic efficiency. BsAT1 transcript expression coincides with increased levels of C3α-O-acetyl-BAs in bark in response to wounding, suggesting a role of BsAT1 in wound-induced biosynthesis of C3α-O-acetyl-BAs. Overall, the results provide new insights into the biosynthesis of principal chemical constituents of Boswellia oleo-gum resin.

Rosin Derivatives as a Platform for the Antiviral Drug Design

The increased complexity due to the emergence and rapid spread of new viral infections prompts researchers to search for potential antiviral and protective agents for mucous membranes among various natural objects, for example, plant raw materials, their individual components, as well as the products of their chemical modification. Due to their structure, resin acids are valuable raw materials of natural origin to synthesize various bioactive substances. Therefore, the purpose of this study was to confirm the possibility of using resin acid derivatives for the drug design. As a result, we studied the cytotoxicity and biological activity of resin acid derivatives. It was shown that a slight decrease in the viral load in the supernatants was observed upon stimulation of cells (II) compared with the control. When using PASS-online modeling (Prediction of Activity Spectra for Substances), the prediction of the biological activity spectrum showed that compound (I) is capable of exhibiting antiviral activity against the influenza virus. The use of the SWISS-ADME webserver to reveal the drug-like properties of compounds did not directly indicate the presence of antiviral activity. These results indicate the potential of resin acid derivatives as a starting point for extensive research in the study of biological activity.

Spruce Bark-Extracted Lignin and Tannin-Based Bioresin-Adhesives: Effect of Curing Temperatures on the Thermal Properties of the Resins

In this study, formaldehyde-free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non-volatile, non-toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR–FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 °C) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross-linking compared to the low temperature-cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures.

Chemical Composition of Volatile Compounds in Apis mellifera Propolis from the Northeast Region of Pará State, Brazil

Propolis is a balsamic product obtained from vegetable resins by exotic Africanized bees Apis mellifera L., transported and processed by them, originating from the activity that explores and maintains these individuals. Because of its vegetable and natural origins, propolis is a complex mixture of different compound classes; among them are the volatile compounds present in the aroma. In this sense, in the present study we evaluated the volatile fraction of propolis present in the aroma obtained by distillation and simultaneous extraction, and its chemical composition was determined using coupled gas chromatography, mass spectrometry, and flame ionization detection. The majority of compounds were sesquiterpene and hydrocarbons, comprising 8.2-22.19% α-copaene and 6.2-21.7% β-caryophyllene, with additional compounds identified in greater concentrations. Multivariate analysis showed that samples collected from one region may have different chemical compositions, which may be related to the location of the resin's production. This may be related to other bee products.

Propolis of stingless bees: A phytochemist's guide through the jungle of tropical biodiversity

BACKGROUND

Stingless bees (Meliponini), like honeybees Apis mellifera, collect plant resins in order to produce propolis (cerumen, geopropolis). This type of propolis has long been used in traditional medicine in Mexico, Brazil, Argentina, India, and Vietnam, as a remedy for improving health and treating various diseases. The scientific and commercial interest in stingless bee propolis has been steadily increasing over the last few years. The new and growing knowledge in this field requires systematising, as a basis for further work. Recent reviews of Meliponini propolis deal only with the South American and Mesoamerican species, while reviews of the Asian, Australian and African species are missing. Furthermore, the chemical composition has not been thoroughly reviewed since 2007.

PURPOSE

This review summarises and discusses the available data about the chemical composition of propolis from the stingless bee species (Meliponinae) of the Americas, Asia and Australia, published after 2007. The published information on the biological action of chemically characterised Meliponini propolis, and of individual constituents, is addressed. The plant sources of this propolis are also considered.

CONCLUSION AND PERSPECTIVES

Chemical studies of Meliponini propolis has resulted in the discovery of new natural molecules, some of them with valuable bioactivity. Moreover, finding known molecules in propolis stimulates the study of their pharmacological properties. The enormous chemical variability of stingless bee propolis is a challenge to chemists, entomologists and pharmacologists. It is essential to perform pharmacological studies with only chemically characterised propolis of stingless bees. Further studies are required to chemically characterise and scientifically support the medicinal properties of stingless bee propolis and to clarify the potential for its commercial use. This could lead to increased prices for Meliponinae propolis and provide an additional source of income for farmers in rural communities with most serious social needs.

Rosin modified aminated mesoporous silica adsorbed tea tree oil sustained-release system for improve synergistic antibacterial and long-term antibacterial effects

Tea tree oil, a natural antibacterial compound, cannot be used effectively because of its volatile nature. In this work, a biocompatible carrier was prepared and loaded with tea tree essential oil. The carrier was prepared via the electrostatic or chemical action of aminated mesoporous silica and sodium rosin for achieving a low volatilization rate of tea tree essential oil. A synergistic antibacterial effect was observed between sodium rosin and tea tree essential oil. This method utilized the positive charge of the amino group and the condensation reaction with the carboxyl group to achieve physical and chemical interactions with sodium rosin. Fourier Transform Infrared, Brunauer-Emmet-Teller, Zeta potential, SEM, TEM, and TG were performed to characterize the structure and properties of the samples. Compared to the electrostatic effect, the chemically modified system exhibited a longer sustained release, and the sustained release curve followed the Korsmeyer-Peppas release model. Also, the antibacterial properties of the chemically modified system exhibited better minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) respectively, the MIC and MBC forE. coliwere 0.3 mg ml^-1and 0.6 mg ml^-1respectively, forS. aureuswere 0.15 mg ml^-1and 0.3 mg ml^-1respectively. More strikingly, the sample also demonstrated long-term antibacterial performance. Therefore, this work provides a new way for the delivery of volatile antibacterial drugs to achieve sustained-release and long-lasting antibacterial effects.

BioAIEgens derived from rosin: how does molecular motion affect their photophysical processes in solid state?

The exploration of artificial luminogens with bright emission has been fully developed with the advancement of synthetic chemistry. However, many of them face problems like weakened emission in the aggregated state as well as poor renewability and sustainability. Therefore, the development of renewable and sustainable luminogens with anti-quenching function in the solid state, as well as to unveil the key factors that influence their luminescence behavior become highly significant. Herein, a new class of natural rosin-derived luminogens with aggregation-induced emission property (AIEgens) have been facilely obtained with good biocompatibility and targeted organelle imaging capability as well as photochromic behavior in the solid state. Mechanistic study indicates that the introduction of the alicyclic moiety helps suppress the excited-state molecular motion to enhance the solid-state emission. The current work fundamentally elucidates the role of alicyclic moiety in luminogen design and practically demonstrates a new source to large-scalely obtain biocompatible AIEgens.

Novel edible coating based on shellac and tannic acid for prolonging postharvest shelf life and improving overall quality of mango

This study aimed to investigate the combined effects of a coating based on shellac and the active agent tannic acid (TA) on the storability and physiological variations of mangoes stored at room temperature. Results showed that TA-shellac prolonged shelf life and improved overall quality of mangoes to a higher extent compared with controls, which was reflected in the extension of shelf life for approximately 10 days, maintaining of tissue firmness and weight loss, slowing down of respiration rate, improvement of physical properties and chemical qualities, suppression of browning, reduction of lipid peroxidation, preservation of aromatic volatiles, and regulation of the related enzymes activities. Addition of TA to shellac coating also improved the antifungal effect of the formulation. The results suggest that a synergistic effect took place between TA and shellac, which demonstrates the high potential for shelf life extension and quality improvement of mangoes of this formulation.

Bioactive Triterpenes of Protium heptaphyllum Gum Resin Extract Display Cholesterol-Lowering Potential

Hypercholesterolemia is one of the major causes of cardiovascular disease, the risk of which is further increased if other forms of dyslipidemia occur. Current therapeutic strategies include changes in lifestyle coupled with drug administration. Statins represent the most common therapeutic approach, but they may be insufficient due to the onset of resistance mechanisms and side effects. Consequently, patients with mild hypercholesterolemia prefer the use of food supplements since these are perceived to be safer. Here, we investigate the phytochemical profile and cholesterol-lowering potential of Protium heptaphyllum gum resin extract (PHE). Chemical characterization via HPLC-APCI-HRMS² and GC-FID/MS identified 13 compounds mainly belonging to ursane, oleanane, and tirucallane groups. Studies on human hepatocytes have revealed how PHE is able to reduce cholesterol production and regulate the expression of proteins involved in its metabolism. (HMGCR, PCSK9, LDLR, FXR, IDOL, and PPAR). Moreover, measuring the inhibitory activity of PHE against HMGR, moderate inhibition was recorded. Finally, molecular docking studies identified acidic tetra- and pentacyclic triterpenoids as the main compounds responsible for this action. In conclusion, our study demonstrates how PHE may be a useful alternative to contrast hypercholesterolemia, highlighting its potential as a sustainable multitarget natural extract for the nutraceutical industry that is rapidly gaining acceptance as a source of health-promoting compounds.

Microencapsulation of probiotic lactobacilli with shellac as moisture barrier and to allow controlled release

BACKGROUND

Rapid dissolution in digestive tract and moisture sorption during ambient storage are the two challenges of dry probiotic preparations. To solve these problems, microcapsules with shellac (LAC) addition containing Limosilactobacillus reuteri TMW 1.656 were designed in this work to provide a good moisture barrier and to provide controlled release in digestive tract, based on the hydrophobicity and acid-resistance of LAC. Four microcapsules were prepared using the method of emulsification/external gelation based on the crosslinking reaction between alginate or LAC with calcium ion, including alginate/sucrose (ALG), alginate/shellac/sucrose (ALG/LAC), alginate/whey protein isolate/sucrose (ALG/WPI) and alginate/whey protein isolate/shellac/sucrose (ALG/WPI/LAC).

RESULTS

Measurements of physical properties showed that microcapsules with LAC addition (ALG/WPI/LAC and ALG/LAC) had larger particle size, much denser structure, lower hygroscopicity and slower solubilization in water, which agreed with the primary microcapsule design. Probiotic survivals in digestive juices followed the order of ALG/WPI/LAC ≥ ALG/WPI ≥ ALG/LAC > ALG. Probiotic stability after heating and ambient storage both exhibited the order of ALG/WPI/LAC > ALG/LAC ≈ ALG/WPI > ALG, which can be explained by the decreased hygroscopicity with adding LAC.

CONCLUSION

LAC addition contributed to better probiotic survivals after freeze drying, simulated digestion, heating and ambient storage, and whey protein isolate (WPI) addition had a synergistic effect. Microcapsule hygroscopicity was closely related with probiotic survivals after heating and ambient storage, while microcapsule solubilization was closely related with probiotic survivals in simulated juices. Within our knowledge, this is the first report to improve probiotic stability during ambient storage based on LAC hydrophobicity. © 2020 Society of Chemical Industry.

Adapting the Accelerated Solvent Extraction Method for Resin and Rubber Determination in Guayule Using the BÜCHI Speed Extractor

Guayule (Parthenium argentatum Gray) is a promising alternative source to Hevea brasiliensis for the production of natural rubber, which can reach levels of 8–9% under industrialized farming conditions. The most common method for determining rubber concentration is by accelerated solvent extraction (ASE), a technique developed by the Dionex Corporation and almost exclusively performed with the Dionex ASE-200 or 350 systems. Herein, it is sought to apply and adapt the most common methods used in the literature for the Dionex system to another extraction platform, the BÜCHI Speed Extractor E-914. Results showed that using a sand sandwich method to confine the sample in the center and exploiting a larger cell volume (80 mL) for extraction prevents the occurrence of overpressure and problems with clogging. Under optimized conditions, the coefficient of variation was <15% for both resin quantification for samples containing 5.0–15.8% of resin and for rubber quantification for samples with 1.7–10.3% rubber content. The extraction time for resin (2 cycles of 5 min each) was smaller than for rubber (2 cycles of 20 min each). It would be interesting to carry out interlaboratory comparisons to standardize the method at an international level.

Anaerobic digestibility of resin acids in primary sludge: Effect of ozone pretreatment

Resin acids in pulp and paper mills wastewater are potentially partitioned in the solids in post-primary clarification due to higher hydrophobicity with log K_ow ∼1.74-5.80. They are known to adversely affect anaerobic digestion (AD) process, although the effect has not been quantified deterministically in control studies. The objective of the present work was to determine the effect of untreated and ozonated spiked resin acids on AD of primary sludge. Batch adsorption tests were conducted to determine the solid-liquid partition coefficient (K_d) of resin acids on the primary sludge. Higher K_d was obtained at pH 4; however, it was decreased by 78-98% at pH 8. Thereafter, batch AD of model resin acids in primary sludge using food to microorganism ratio (S₀/X) of 0.5gtCOD/gVSSindicated only 15-20% removal of resin acids in the liquid phase anaerobically. While, ozonation in pure water using 0.74-1.48 mg O₃/mg tCOD showed >90% reduction of the test resin acids, an ozone dose of 0.52 mg O₃/mg tCOD reduced 50-70% spiked resin acids' load to the digester. However, no further removal of resin acids occurred during AD over 30 days. About 42% reduction in methane production compared to the control digestor occurred in the presence of 150 mg/L of resin acids. When treated with 0.52 mg O₃/mg tCOD, methane production improved and was comparable to the control digestor, indicating that resin acids may not be detrimental to AD at a concentration range of 45-75 mg/L.

Stability of Alum-Containing Paper under Alkaline Conditions

The present contribution evaluates the methods of degradation and stabilization of alum-containing paper with a focus on the alkaline environment achieved by deacidification procedures. In terms of reviewed subjects, the contribution focuses on alum-rosin sized paper, which is still used as a carrier of knowledge and information; however, it also mentions cellulose itself and other brands of paper. The contribution summarizes the results on the homogeneity of the distribution of alum and rosin in the paper mass and on the paper surface. It provides the knowledge gained in the field of alkaline hydrolysis and oxidation with special regard to transition metal species. It shows the values of alkaline reserves achieved in the main mass-deacidification processes. On the basis of the acquired knowledge, the contribution emphasizes the procedures of paper stabilization. Criteria of “increased mechanical permanence and lifetime prolongation” adopted to evaluate and compare the efficacy of individual mass-deacidification processes were applied and corresponding data are introduced. The contribution also draws attention to the existence of open issues in the area of paper degradation and stabilization.

Contemporary analytical techniques reveal the secret composition of a 19th century Jerusalem Balsam

In 1719, Antonio Menzani di Cuna from the Saint Savior monastery published an alcoholic extract formula made from plant and herb resins under the name Jerusalem Balsam. The Balsam gained high popularity due to its remedial benefits. At the end of the 19 th century, Jerusalem Balsam produced by the hermit Johannes Treutler was found to be particularly popular. We analysed a sample of a valuable find coming from the last decade of the 19 th century, making it probably the oldest surviving Jerusalem Balsam in the world. The purpose of this work was to investigate the composition of the historical sample and to try to determine the origin of its components. This was achieved by comparing the profile of volatile compounds extracted from the balsam using HS-SPME technique with the profile characteristic for plant resins as classic ingredients of the Johannes Treutler formula. The use of two chromatographic columns of different polarity, as well as the transformation of the polar components of the sample into TMS derivatives, allowed to obtain new information on the historical composition of the Balsam. Also, it can be stated with high probability that plant resins were indeed used in the production of the Balsam as referred to in the original recipe of Johannes Treutler. We also discuss challenges in determining the original composition of the Balsam.

Roles of ethylene, jasmonic acid, and salicylic acid and their interactions in frankincense resin production in Boswellia sacra Flueck. trees

The roles of ethylene, jasmonic acid, and salicylic acid and their interactions in frankincense resin production in Boswellia sacra trees growing in the drylands of Oman were studied. On March 18 (Experiment 1) and September 17 (Experiment 2), 2018, 32-year-old B. sacra trees with multiple trunks were selected at the Agricultural Experiment Station, Sultan Qaboos University, Oman. Various lanolin pastes containing Ethrel, an ethylene-releasing compound; methyl jasmonate; sodium salicylate; and combinations of these compounds were applied to debarked wounds 15 mm in diameter on the trunks. After a certain period, the frankincense resin secreted from each wound was harvested and weighed. The anatomical characteristics of the resin ducts were also studied in the bark tissue near the upper end of each wound. The combination of Ethrel and methyl jasmonate greatly enhanced frankincense resin production within 7 days in both seasons. The application of methyl jasmonate alone, sodium salicylate alone or a combination of both did not affect resin production. These findings suggest a high possibility of artificial enhancement of frankincense resin production by the combined application of Ethrel and methyl jasmonate to B. sacra trees.

DNA from resin-embedded organisms: Past, present and future

Past claims have been made for fossil DNA recovery from various organisms (bacteria, plants, insects and mammals, including humans) dating back in time from thousands to several million years BP. However, many of these recoveries, especially those described from million-year-old amber (fossil resin), have faced criticism as being the result of modern environmental contamination and for lack of reproducibility. Using modern genomic techniques, DNA can be obtained with confidence from a variety of substrates (e.g. bones, teeth, gum, museum specimens and fossil insects) of different ages, albeit always less than one million years BP, and results can also be obtained from much older materials using palaeoproteomics. Nevertheless, new attempts to determine if ancient DNA (aDNA) is present in insects preserved in 40 000-year old sub-fossilised resin, the precursor of amber, have been unsuccessful or not well documented. Resin-embedded specimens are therefore regarded as unsuitable for genetic studies. However, we demonstrate here, for the first time, that although a labile molecule, DNA is still present in platypodine beetles (Coleoptera: Curculionidae) embedded in six-year-old and two-year-old resin pieces from Hymenaea verrucosa (Angiospermae: Fabaceae) collected in Madagascar. We describe an optimised method which meets all the requirements and precautions for aDNA experiments for our purpose: to explore the DNA preservation limits in resin. Our objective is far from starting an uncontrolled search for aDNA in amber as it was in the past, but to start resolving basic aspects from the DNA preservation in resin and search from the most modern samples to the ancient ones, step by step. We conclude that it is therefore possible to study genomics from resin-embedded organisms, although the time limits remain to be determined.