Bioactive pentacyclic triterpenes from the stems of Combretum laxum

Echinograciolide, a new antibacterial nor-triterpenoid and other constituents from Echinops gracilis O. Hoffm. (Asteraceae)

Antibacterial resistance is a serious threat against humankind and the search for new therapeutics is needed. This study aims to investigate the antibacterial activity of extracts and compounds from Echinops gracilis O. Hoffm. Standard chromatographic and spectroscopic methods were used to isolate and characterize compounds (1-15) from the methanol extract. The extract, chromatographic fractions and compounds 1-3, 8, 11, 13 and 14 were subjected to in vitro antibacterial assays against Staphylococcus aureus ATCC25923, Salmonella Typhi ATCC6539, Klebsiella pneumoniae 22, and Salmonella Typhi 68, using broth micro-dilution method. As results, a new nor-triterpenoid (1) and fourteen known compounds (2-15) were characterized. The extract and fractions displayed moderate (128 ≤ MIC ≤ 512 μg/mL) and significant (MIC 64 μg/mL) antibacterial activities. Compounds 1 and 14 showed the best anti-staphylococcal and anti-salmonella activity (MIC 16 µg/mL), respectively. These results partially justified the antimicrobial uses of E. gracilis in traditional medicine.

Diverse terpenoid glycosides with in vitro cytotoxicity from Glechoma longituba

Terpenoids are the largest class of all known natural products, possessing structural diversity and numerous biological activities. Ten previously undescribed terpenoid glycosides, glechlongsides A-J (1-10), were isolated from the ethanol extract of the whole plant of Glechoma longituba, including diterpenoid glycoside and pentacyclic triterpenoid saponin. The structures of these compounds were characterized by extensive analysis of 1D and 2D NMR as well as HRESIMS spectra. In addition, glechlongsides F-I (6-9) exhibited weak cytotoxicity against human cancer cell lines BGC-823, Be1, HCT-8, A2780, and A549 with IC50 values ranging from 3.77 to 30.95 μM, respectively.

Four New Pentacyclic Triterpene Glycosides Isolated from the Fruits of Cryptolepis buchananii R.Br. ex Roem. & Schult and Their Inhibition of NO Production in LPS-activated RAW264.7 Cells

From the methanol extract of the Cryptolepis buchananii fruits, four undescribed pentacyclic triterpenene glycosides (1-4) and five known pentacyclic triterpenenes (5-9) were isolated. Their structures were determined to be uncargenin C 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (1), 3-O-β-D-glucopyranosyluncargenin C 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (2), 3-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyl-6β,23-dihydroxyursolic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (3), 3-O-β-D-glucopyranosyl-(1→2)-β-D-glucopyranosylasiatic acid 28-O-α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranosyl ester (4), asiatic acid (5), 2α,3β,23-trihydroxyoleana-11,13(18)-dien-28-oic acid (6), arjunolic acid (7), 6β-hydroxyarjunolic acid (8), and actinidic acid (9) based on analyses of their HR-ESI-MS, 1D and 2D NMR spectra. All the isolates showed significantly NO production inhibition in LPS-activated RAW264.7 cells with the IC50 values ranging from 18.79 to 37.57 μM, compared to that of the positive control compound, dexamethasone, which showed IC50 value of 14.05 μM.

Antibacterial stigmastane-type steroids and other constituents from the leaves of Vernonia glabra (Steetz) Vatke (Asteraceae)

Two new stigmastane steroids (1 and 2) were isolated from the methanol extract of the leaves of Vernonia glabra, together with seventeen known compounds (3-19) including one fatty acid, four triterpenoids, four steroids, one trinitropropanoyl glucoside, and seven flavonoids. The structures of compounds 1 and 2 were assigned based on their IR, NMR and MS data, and by comparison with literature values. The MeOH extract, its fractions and isolated compounds were subjected to in vitro antibacterial assay against two Gram-positive (Staphylococcus aureus ATCC25923 and Streptococcus pneumoniae ATCC49619) and two Gram-negative (Escherichia coli ATCC8739 and Klebsiella pneumoniae ATCC10031) bacteria, using broth microdilution method. The extract and fractions exhibited (16 ≤ MIC ≤ 512 μg/mL) antibacterial activities. The isolated and tested compounds were also active (16 ≤ MIC ≤ 128 μg/mL) against the four pathogenic bacteria, with compound 2 being the most active and E. coli, the most sensitive microorganism.

Siamoside A: a new C-glycosylated flavone from Senna siamea (Lam.) H. S. Irwin & Barneby (Caesalpiniaceae)

Phytochemical investigation of the methanol extracts from the leaves and bark of Senna siamea resulted in the isolation of one new flavone C-glycoside: apigenin-8-C-[6''-(E)-feruloyl]-β-D-glucopyranoside] (1), together with sixteen known compounds including quercetin-3-O-α-L-rhamnoside (2), vitexin (3), isovitexin (4), quercetin-3-O-β-D-glucopyranoside (5), quercetin-3-O-β-D-arabinopyranoside (6), quercetin (7), kaempferol (8), methyl inositol (9), sucrose (10), betulinic acid (11), vanillic acid (12), stigmastane-3β,6α-diol (13), aurantiamide acetate (14), robinetinidol (15), catechin (16) and epicatechin (17). The structures of these compounds were established on the basis of their spectroscopic (1 D and 2 D NMR) and mass spectrometric (ESI-TOF-MS) data. The methanol extracts, fractions and some of the isolated compounds were screened for their antimicrobial properties against five microbial strains. The methanol extract and the ethyl acetate fraction from the bark showed very weak antifungal activity against C. glabrata with the same MIC value of 128 μg/mL. Compound 7 was weakly active against C. albicans with MIC of 32 μg/mL.

Mimonoside D: a new triterpenoid saponin from Mimosa diplotricha Sauvalle (Fabaceae)

A new triterpenoid saponin (Mimonoside D: 3-O-α-L-arabinopyranosyl-3β-hydroxyolean-12-en-28-oic acid 28-O-β-D-xylopyranosyl-(1→2)-β-D- glucopyranoside ester (1)) was isolated from the aerial parts of Mimosa diplotricha Sauvalle together with nine known compounds: 7,4'-dihydroxyflavone (2), kaempferol (3), lupeol (4), betulinic acid (5), β-sitosterol (6), β-sitosterol-3-O-β-D-glucopyranoside (7), lutein (8), 5,2'-dihydroxy-7,4',5'-trimethoxyflavone (9) and vitexin (10). Their structures were elucidated on the basis of spectroscopic (1 D and 2 D nuclear magnetic resonance) and high-resolution mass spectrometric data as well as by comparison of their spectral data with those of related compounds. Compounds 2, 7 and 8 had already been isolated from M. diplotricha, while compounds 3, 4, 5 and 6 have been isolated from other Mimosa species. Compound 2 moderately inhibited Proteus mirabilis (MIC = 32 µg/mL), weakly inhibited Pseudomonas aeruginosa (MIC = 64 µg/mL) and very weakly inhibited Staphylococcus aureus (MIC = 128 µg/mL) and Enterococus faecalis (MIC = 128 µg/mL).

Development of an Analytical Workflow to Support the Establishment of Monographs in African Pharmacopoeias - Combretum mucronatum Leaves as Example

Herbal medicines are invaluable in African medicine, but quality and safety are not documented in many cases. Besides controlled farming, validated quality control methods are needed to ensure identity, purity, and content. Analytical specifications within modern monographs are needed for consistent batch quality. Combretum mucronatum leaves are widely used in West Africa, but state-of-the-art quality control methods and specifications are non-existent. The aim of the following study was the development of ICH-validated chromatographic protocols for identity, purity, content assay, and analytical specifications for consideration into pharmacopoeial monographs. UPLC-ESI-Q-TOF-MS/MS was used for untargeted phytochemical information on composition. Optimisation of extraction was based on phytochemical profiling. HPTLC was used for differentiation of C. mucronatum from other Combretum species and UPLC for simultaneous determination of 7 marker compounds. C. mucronatum batch analyses (n = 49) investigated the influence of harvest time and geographical origin. Pesticides screening from a 349-compound panel were carried out. 30 compounds, identified by LC-MS, were used for characterization of the plant material. Orietin, isoorientin, vitexin and isovitexin were used as specific marker compounds for qualitative and quantitative HPTLC purposes, while UPLC quantified additionally epicatechin, procyanidins B2 and C1. Influence of harvest time and geographic origin on the content of marker compounds was observed. Differences in the metabolite profiles of C. mucronatum compared to related Combretum species were established for quality control purposes. Contamination with high amoounts of chlorpyrifos, and folpet (sum of folpet and phtalimide, expressed as folpet) were also observed.The study provides analytical protocols, analytical specifications and a drafted monograph for consideration for African pharmacopoeias, and reveals potential challenges in the quality of C. mucronatum.

Discovery of Anti-Inflammatory Triterpenoid Glucosides from the Heritiera littoralis Dryand

Two new triterpenoid glucosides, Heritiera A (1) and Heritiera B (2), and six known triterpenoid analogs (3-8) were isolated from Heritiera littoralis Dryand. Their structures were identified by comprehensive spectroscopic analyses and comparisons with the literature. The anti-inflammatory activity of the isolates from H. littoralis was evaluated using a lipopolysaccharide (LPS) stimulated RAW 264.7 cells model. The result showed that four triterpenoids exhibited potent anti-inflammatory activity. Among these compounds, compound 2 substantially inhibits the release of nitric oxide (NO) with an IC₅₀ value of 10.33 μM. The triterpenoids from H. littoralis could be used as potential candidates for the development of new anti-inflammatory agents.

Minor terpenoids from the stems and twigs of Rhododendron ovatum

Four minor undescribed terpenoids, including a monoterpenoid (1) and three triterpenoids (3, 6 and 7), together with 26 known terpenoids were isolated from the stems and twigs of Rhododendron Ovatum. Their structures were identified by extensive spectroscopic analyses and electronic circular dichroism (ECD) techniques. Compound 10 showed excellent cytotoxicity against human colon cancer cell (HCT-116) with IC₅₀ value of 2.56 μM. Compounds 9 and 19 exhibited partly inhibitory effects on nitric oxide production stimulated by lipopolysaccharide-induced neuroinflammation in microglia cells at 10 μM with inhibition ratios of 39.70% and 28.08%, respectively.

Combined Computational NMR and Molecular Docking Scrutiny of Potential Natural SARS-CoV-2 Mpro Inhibitors

In continuation of the search for potential drugs that inhibit the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in this work, a combined approach based on the modeling of NMR chemical shifts and molecular docking is suggested to identify the possible suppressors of the main protease of this virus among a number of natural products of diverse nature. Primarily, with the aid of an artificial neural network, the problem of the reliable determination of the stereochemical structure of a number of studied compounds was solved. Complementary to the main goal of this study, theoretical modeling of NMR spectral parameters made it feasible to perform a number of signal reassignments together with introducing some missing NMR data. Finally, molecular docking formalism was applied to the analysis of several natural products that could be chosen as prospective candidates for the role of potential inhibitors of the main protease. The results of this study are believed to assist in further research aimed at the development of specific drugs based on the natural products against COVID-19.

Isolation of two new triterpene glycoside from the fruits of Terminalia arjuna and their in vitro and in silico studies

Two new triterpene glycoside, Arjunoglycoside VI (1) and Arjunursglycoside I (2) alone with five previously known analogues (3-7) were isolated from methanolic extract of the fruits of Terminalia arjuna. The structures were elucidated by extensive spectroscopic studies (1 D and 2 D NMR and mass). Compound 1 and 2 showed moderate activity on α-chymotrypsin enzyme inhibition with IC₅₀ values 53.8 ± 1.39 and 64.27 ± 1.27 µg/mL respectively. Molecular docking was performed for compound 1 and 2 with the 1CGI co crystals of α-chymotrypsin enzyme protein of Bovine from protein data bank showed -7.7 and -7.6 kcal/mol binding energy, respectively.

Selective tumor cell growth inhibition by lignans and a seco-triterpenoid from Combretum mellifluum

Two new tetrahydrofuran lignans 1-2, along with 2,3-seco-lup-20(29)-en-2,3-dioic acid (3), (-)-larreatricin (4), and 15 additional compounds were isolated from Combretum mellifluum (Combretaceae). Their structures were determined by 1D- and 2D- NMR spectroscopic data and HRESIMS. Another 15 compounds were identified after HPLC-DAD-MS/MS analysis. Tested against HT-29 (colon) neoplastic cells, lignan 1 showed marked cytotoxicity (GI₅₀ = 3.9 µM) and high selectivity (SI > 227), compared with non-neoplastic NIH/3T3 cells, while 2 proved less cytotoxic, despite exhibiting SI > 75. Seco-triterpene 3 was strongly cytotoxic to 786-0 (kidney) and HT-29 cells (GI₅₀ = 0.5 and 2.9 µM, respectively), proving roughly 107 and 18 times more selective for these cell lines, respectively, than for NIH/3T3 cells. After 48 h of incubation, 1-3 exhibited potent cytostatic activity against HT-29 cells at all concentrations tested, while 3 had a cytocidal effect on 786-0 cells at 25 µg.mL^-1.

Bioassay Directed Fractionation of Petroleum Ether Extract of Aerial Parts of Ceriops tagal: Isolation of Lupeol as the Nematicidal Agent against Cyst Nematode Heterodera zeae

Plant parasitic cyst nematode  Heterodera zeae  is a pest, causing substantial economic losses in agriculture. Organic pesticides, based on plant products have emerged as eco-benign nematicidal agents.  Ceriops tagal  is a well-known marine medicinal plant which has not been evaluated against any nematode. Petroleum ether extract of the aerial parts of the plant (CTP), exhibited promising activity against infective stage larvae of  H. zeae . On subjecting to classical solvent-solvent separation, it afforded petroleum ether soluble (CTP-S), methanol soluble ( CTPMS-1 , CTPMS-2) and insoluble (CTPM-IN-2) fractions, which exhibited activity against the cyst nematode within 24 h exposure. GC, GCMS and ESI-HRMS analyses of CTPMS-1 and CTPMS-2 fractions resulted in the identification of a number of compounds, including pentacyclic triterpenoids, lupeol ( 1 ), betunal ( 2 ), betulin ( 3 ), lupenone ( 4 ), betulonaldehyde ( 5 ), betulonic acid ( 7 ), methyl-3-acetoxy-27- O -(3,4-dihydroxy- E -cinnamoyl)-20(29)-lupen-28-oate ( 8 ) and  β -amyrin, along with phenylpropanoid esters, fatty acids and their derivatives, benzamide, and indole derivatives. CTPM-IN-2 which mainly contained lupeol ( 1 ) exhibited maximum nematicidal activity, with 91% and 93% mortality of the larvae of  H. zeae , after exposure for 72 h at the concentration of 0.5% and 1%, respectively. Its fractionation and purification through column chromatography resulted in the isolation and identification of four lupane-type triterpenoids  1 ,  3 ,  4  and betulinic acid ( 6 ). One of its most abundant column fractions CC-9-18 (145 mg) which exhibited substantial activity, with 81% mortality at the lowest concentration of 0.125% after 48 h of incubation mainly contained lupeol. It seems lupeol, a wide spread bio-privileged triterpenoid is the nematicidal principle of the plant as its authentic sample showed LC 50 value of 0.061 after 72 h exposure. It is for the first time that nematicidal activity is reported for any part of  C. tagal  and that of lupeol against  H. zeae.  Pentacyclic triterpenoids  1 - 8  are biosynthetically related. Of the twenty-four compounds isolated or identified in the present investigation only five constituents  1 ,  3 ,  6 ,  7  and palmitic acid have been isolated previously from  C. tagal .

Antibacterial and cytotoxic activities of undescribed cassiaric acid and other constituents from Cassia arereh stem barks

A new lupane-type triterpene, 2α,3β-dihydroxylupan-29-oic acid (1), and one new ceramide derivative: (2S*,2'R*,3S*,4R*,5R*,7'E,11E,12'E,20E)-N-[2'-hydroxyoctadeca-6,11-dienoyl]-2-aminohexacosa-11,20-diene-1,3,4,5-tetrol (2) were isolated from the ethyl acetate fraction obtained from the methanol extract of the stem barks of Cassia arereh together with seven known compounds. Their structures were characterized using two-dimensional NMR, mass spectrometry, and compared with reported data. To date, this is the first report of the isolation of a multiple double bonds sphingolipid type (2) from this genus. The ethyl acetate extract and selected isolates were examined for antimicrobial and cytotoxic activities in vitro. Betulinaldehyde (5) has shown to be active against all bacterial strains whereas, cassiaric acid (1) and betulinic acid (6) have demonstrated to be moderately active. In addition, cassiaric acid (1) showed the best cytotoxic result against HeLa and MCF-7 cell lines tested with IC₅₀ 75.00 µM, while lupeol (3) and betulinic acid (6) displayed weak cytotoxicity at 100.00 µM.

Antifungal activity and potential mechanism of Asiatic acid alone and in combination with fluconazole against Candida albicans

Candida albicans (C. albicans) infection remains a challenge to clinicians due to the limited available antifungals. With the widespread use of antifungals in the clinic, the drug resistance has been emerging continuously, especially fluconazole. Therefore, searching for new antifungals, active constituents of natural or traditional medicines, and approaches to overcome antifungals resistance is needed. This study investigated the activity of Asiatic acid (AA) alone and in combination with fluconazole (FLC) against C. albicans in vitro and in vivo. The in vitro studies indicated that the drug combination had a synergistic effect on FLC-resistant C. albicans, with fractional inhibitory concentration index (FICI) of 0.25. And when AA at the dose of 32 µg/mL, the drug combination group could decrease the sessile minimum inhibitory concentration (sMIC) of FLC from > 1024 µg/mL to 0.125-0.25 µg/mL within 8 h against C. albicans biofilms, even with the FICI > 0.5. In vivo, the antifungal efficacy of AA used alone and in combination with FLC was evaluated by Galleria mellonella (G. mellonella) larvae. The drug combination group prolonged the survival rate and reduced tissue invasion of larvae infected with resistant C. albicans. Furthermore, mechanism studies indicated that the antifungal effects of AA in combination with FLC might be associated with the inhibition of drug efflux pump, the accumulation of reactive oxygen species (ROS) and the inhibition of hyphal growth. These findings might provide novel insights for overcoming drug resistance of C. albicans and bring new reference data for the development and application of AA in future.

Isolation and characterization of anti-inflammatory and analgesic compounds from Uapaca staudtii Pax (Phyllanthaceae) stem bark

ETHNOPHARMACOLOGICAL RELEVANCE

Uapaca species including Uapacastaudtii Pax (Phyllanthaceae) are used in West Africa ethnomedicine to treat diverse ailments including pile, rheumatism, oedema and wound healing. However, the anti-inflammatory and analgesic potential as well as constituents of the Uapacastaudtii stem bark has not been investigated.

AIM OF THE STUDY

The study was designed to evaluate the anti-inflammatory, analgesic, and antioxidant activities of extract and fractions ofU. staudtii stem bark, and to isolate the bioactive constituents.

MATERIALS AND METHODS

The anti-inflammatory, analgesic and antioxidant activities of the ethanol extract, dichloromethane, ethyl acetate, butanol, and aqueous fractions of U. staudtii stem bark, as well as protocatechuic acid and betulinic acid isolated from the bioactive ethyl acetate fraction were evaluated in different mice models of inflammation and pain; furthermore, antioxidant assays were carried out. Chemical structures of isolated compounds were established based on spectroscopic studies and comparison with literature data.

RESULTS

The ethanol extract and ethyl acetate fraction exhibited good anti-inflammatory, analgesic, and antioxidant capacity in all studied models, comparable with those of the standard drugs used. Protocatechuic acid also gave significant (p < 0.05) anti-inflammatory (83%and 88% inhibition for egg-albumin induced and xylene induced oedema, respectively), analgesic (56% inhibition and 22 s of pain suppression for acetic acid-induced and hot plate-induced pain, respectively), and antioxidant effects (97% inhibition and absorbance of 2.516 at 100 μg/mL for DPPH and FRAP assay, respectively) in all the models, whereas betulinic acid only exhibited significant (p < 0.05) anti-inflammatory and antioxidant activity.

CONCLUSIONS

The result supports the medicinal uses of the U. staudtii stem bark in the management of pain and inflammatory disease. This is the first report on the biological activities and characterization of compounds inU. staudtii, and presence of protocatechuic acid in Uapaca genus.

Isolation and identification of two new sargentodoxosides from Sargentodoxa cuneata and their agonistic effects against FXR

Sargentodoxa cuneata (Oliv.) Rehd. et Wils is a traditional Chinese medicine to treat acute appendicitis, rheumarthritis, abdominal pain, and painful menstruation for a long history. The investigation of S. cuneata led to the isolation and identification of twenty-three secondary metabolites, including two new compounds, sargentodoxosides A (1) and B (2), and twenty-one known ones (3-23). Their structural characterization was conducted by HRESIMS, 1 D and 2 D NMR spectra. All the isolated compounds were assayed for their agonistic activities against the farnesoid X receptor (FXR). Nine of the isolated compounds displayed significant agonistic effects against FXR at 0.1 µM, suggesting that they could be served as potential agents for the development of FXR agonists.

Antiproliferative activity of a new xanthone derivative from leaves of Garcinia nobilis Engl

A new xanthone, mboudiexanthone (1), together with five known compounds, euxanthone (2), isogarcinol (3), garcinol (4), betulinic acid (5) and zeorin (6) were isolated from the leaves of Garcinia nobilis Engl. The structures were determined by 1D and 2D NMR techniques and X-ray diffraction for 6. The in vitro antiproliferative properties of isolated compounds were evaluated against the human breast cancer cell line MCF-7. All compounds showed an antiproliferative activity with an IC₅₀ value down to ∼11 µM for isogarcinol.

Cytotoxic Phenanthrene, Dihydrophenanthrene, and Dihydrostilbene Derivatives and Other Aromatic Compounds from Combretum laxum

The chemical investigation of the roots and stems of Combretum laxum yielded a new dihydrostilbene derivative, 4'-hydroxy-3,3',4-trimethoxy-5-(3,4,5-trimethoxyphenoxy)-bibenzyl (1), two phenanthrenes (2-3), and three dihydrophenanthrenes (4-6), along with one lignan, three triterpenoids, one aurone, one flavone, one naphthoquinone, and two benzoic acid derivatives. Their structures were determined by 1D and 2D nuclear magnetic resonance (NMR) spectroscopic techniques and/or mass spectrometry data. The occurrence of dihydrostilbenoid, phenanthrene and dihydrophenanthrene derivatives is unprecedented in a Combretum species native to the American continent. 2,7-Dihydroxy-4,6-dimethoxyphenanthrene, 2,6-dihydroxy-4,7-dimethoxy-9,10-dihydrophenanthrene and 5-O-methyl apigenin are novel findings in the Combretaceae, as is the isolation of compounds belonging to the chemical classes of aurones and naphthoquinones, while (+)-syringaresinol is reported for the first time in the genus Combretum. Compounds 1-6 were also evaluated for their in vitro cytotoxicity against five human cancer cell lines, and radical-scavenging ability against 1,1-diphenyl-2-picryl-hydrazyl (DPPH). 6-Methoxycoelonin (4) was the most cytotoxic against melanoma cells (IC₅₀ 2.59 ± 0.11 µM), with a high selectivity index compared with its toxicity against nontumor mammalian cells (SI 25.1). Callosin (6), despite exhibiting the strongest DPPH-scavenging activity (IC₅₀ 17.7 ± 0.3 µM), proved marginally inhibitory to the five cancer cell lines tested, indicating that, at least for these cells, antioxidant potential is unrelated to antiproliferative activity.

Phenylpropanoid-Conjugated Triterpenoids from the Leaves of Actinidia arguta and Their Inhibitory Activity on α-Glucosidase

Actinidia arguta, commonly called hardy kiwifruit or kiwiberry, has cold-resistant properties and can be cultivated in Asia, including Korea. Seven new triterpenoids (2-4 and 8-11) along with eight known triterpenoids were isolated from the leaves of A. arguta through various chromatographic techniques. The new triterpenoids were defined as actiniargupenes A-C (2-4), actinidic acid derivatives with phenylpropanoid constituent units, dehydroisoactinidic acid (8), and actiniargupenes D-F (9-11), asiatic acid derivatives with phenylpropanoid substituents, on the basis of 1D and 2D NMR and MS data. Among the triterpenoids, those with a phenylpropanoid constituent unit showed inhibitory activity on α-glucosidase, which suggested the importance of the phenylpropanoid moiety. Molecular docking analysis demonstrated the interaction between the 4'-OH group of the phenylpropanoid moiety and α-glucosidase.

Reductive Metabolism of Ellagitannins in the Young Leaves of Castanopsis sieboldii

The leaves of Castanopsis sieboldii (Fagaceae) contain characteristic hexahydroxydiphenoyl (HHDP) esters of 28-O-glucosyl 2α,3β,23,24-tetrahydroxyolean- and urs-12-en-28-oic acids. In this study, uncharacterized substances were detected in the young leaves, which are not observed in the mature leaves. Preliminary HPLC analyses indicated that the substances had dehydro-HHDP (DHHDP) ester groups; however, the esters were unstable and decomposed during extraction. Therefore, the compounds were isolated as their stable phenazine derivatives by extracting the young leaves with acidic aqueous EtOH containing o-phenylenediamine. The structures of the phenazine derivatives indicated that the unstable metabolites of the young leaves were 3,24-DHHDP esters of the abovementioned triterpenes. Extraction of the young leaves with 80% acetonitrile containing reducing agents, ascorbic acid or dithiothreitol afforded the corresponding HHDP esters. Furthermore, heating of the young leaves in 80% acetonitrile also yielded the same HHDP esters as the reduction products. The results suggested that the HHDP esters are reductively produced from DHHDP esters in the young leaves. In addition, the structures of five previously reported triterpene HHDP esters were revised.

Anti-inflammatory and phytochemical evaluation of Combretum aculeatum Vent growing in Sudan

ETHNOPHARMACOLOGICAL RELEVANCE

Combretum aculeatum Vent was traditionally used in Sudan, Eretria and Ethiopia as anti-inflammatory in case of skin inflammation, catarrh, wounds, scorpion stings and snake bites. Nevertheless, there is no scientific information regarding this activity.

AIM OF STUDY

The present study aimed to evaluate the phytochemical constituents and the scientific basis for the traditional use of Combretum aculeatum Vent through studying its anti-inflammatory properties for the first time to illustrate the putative mechanisms behind this bioactivity.

MATERIALS AND METHODS

the ethanolic extract was partitioned by petroleum ether, methylene chloride, ethyl acetate, and n-butanol saturated with water. The petroleum ether fraction was saponified and the saponifiable and unsaponifiable fractions were analyzed on GC/MS. The different fractions were subjected to phytochemical investigation to isolate pure compounds. In-vivo anti-inflammatory activity of the ethanolic extract was evaluated using carrageenan induced rat paws edema method at doses of 200, 400 and 600 mg/kg and proved based on histopathological and biochemical parameters.

RESULTS

Five known compounds were isolated for the first time from the aerial parts of Combretum aculeatum Vent: quercetin, vitexin, isorhamnetin 3-O-β-glucoside, isovitexin and rutin, in addition to two previously isolated ones: β-sitosterol and its glucoside. The ethanolic extract evidenced in-vivo anti-inflammatory activity by oral intake of 400 mg/kg of the ethanolic extract significantly (P ≥ 0.05) decreased the paw edema (only 32±1.9% increase in paw weight after 4 h) compared to indomethacin (28.6±2.5%). Moreover, it significantly suppressed the serum malondialdehyde (MDA) and nitric oxide (NO) and increased the GSH to be 11.76±0.85, 5.13±0.62 μmol/mL and 5.66±0.28 μM/mL, respectively. It diminished the serum cytokines TNF-α, IL-6 and IL-1β levels to be 39.1±1.2, 32.6±1.1 and 37.5±1.2 pg/mL, respectively. Results are accompanied by histopathological examination.

CONCLUSION

Overall, the results herein presented significant anti-inflammatory properties traditionally ascribed to Combretum aculeatum Vent. Moreover, the biochemical mechanisms associated to this action were highlighted, introducing new prospects for the development of effective anti-inflammatory herbal medicinal products.

Evaluation of Anti-HIV-1 Integrase and Anti-Inflammatory Activities of Compounds from Betula alnoides Buch-Ham

Betula alnoides is a medicinal plant in Thai traditional longevity preparations. The crude extracts of this plant possess various biological activities. However, the isolated compounds from this plant have no reports of anti-HIV-1 integrase (IN) activity. Therefore, the present study aims to investigate the anti-HIV-1 integrase and anti-inflammatory effects of isolated compounds from this plant and predict the interaction of compounds with integrase active sites. From the bioassay-guided fractionation of the ethanol extract of B. alnoides stems using chromatographic techniques, five pentacyclic triterpenoid compounds were obtained. They are betulinic acid (1), betulin (2), lupeol (3), oleanolic acid (4), and ursolic acid (5). Compound 2 exhibited the most potent inhibitory activity against HIV-1 IN, with an IC₅₀ value of 17.7 μM. Potential interactions of compounds with IN active sites were investigated using computational docking. The results indicated that active compounds interacted with Asp64, a residue participating in 3′-processing, and Thr66, His67, and Lys159, residues participating in strand-transfer reactions of the integration process. Regarding anti-inflammatory activity, all compounds exerted significant inhibitory effects on LPS-induced nitric oxide production (IC₅₀ < 68.7 μM). Thus, this research provides additional scientific support for the use of B. alnoides in traditional medicine for the treatment of HIV patients.

Bioactivity-Guided Isolation and Identification of Antiadipogenic Compounds in Shiya Tea (Leaves of Adinandra nitida)

Obesity is a worldwide epidemic contributing to a higher risk of developing maladies such as type 2 diabetes, heart disease, and cancer. Shiya tea (leaves of Adinandra nitida), a traditional Chinese tea, is widely consumed due to its palatable flavor and various curative effects, such as reducing blood pressure and blood lipids, as well as anti-inflammation, etc. However, no relevant research on the antiobesity effects of Shiya tea has been reported. In particular, no health-benefiting compounds, other than flavonoids, in Shiya tea have been reported. Thus, 3T3-L1 preadipocytes have been used as a bioactivity-guided identification model to verify the inhibitory effects of Shiya tea on adipogenesis, as well as to identify antiadipogenic compounds. Four triterpenoid saponins (1-4), including one new compound (2α,3α-dihydroxyursolic acid 28- O-β-d-glucopyranosyl ester, compound 1), and a flavonoid (5) have been identified using NMR (1D and 2D NMR) and liquid chromatography (LC)-MS techniques. Compound 1, the major antiadipogenic constituent with an IC₅₀ value of 27.6 μg/mL, has been identified for the first time in Shiya tea. To understand the structure-activity relationship, three hydrolytic compounds (1s, 2s, and 5s) were obtained to provide an inhibitory effect on lipid accumulation during 3T3-L1 adipocyte differentiation. The inhibitory effect of the triterpenoid (1s) possessing no sugar group decreased significantly, while the flavonoid (5s) also without a sugar group showed increased activity. In addition, the hydroxyl group position may also play a role in inhibitory efficacy.

Unmodified household coffee maker assisted extraction and purification of anticancer agents from Dillenia indica fruits

Bioassay targeted, 80% aqueous ethanol crude extract of the fruits of Dillenia indica Linn, using the unmodified household coffee maker, afforded five compounds, namely betulinic acid (1), rhamnazin (2), dillenetin (3), luteolin-7-O-β-D-glucoside (4) and hypolaetin-8-O-β-D-glucoside (5). The crude extract, fractions and purified compounds were tested against MDA MB-231, A549 and HeLa cancer cell lines by MTT assay, using betulinic acid 1, as a positive control. Compound 3 showed the best activity against A549 (IC₅₀ = 26.60 ± 2.5 µM) and HeLa cancer cell lines (IC₅₀ =19.35 ± 0.9 µM), whereas compound 5 was found to show the best activity against MDA MB-231 (IC₅₀ = 34.62 ± 5.2µM) cancer cell line. These highly potent anticancer compounds obtained from the fruits of D. indica may be suitable for herbal drug development and formulations.

Antibacterial activities of triterpenoidal compounds isolated from Calothamnus quadrifidus leaves

Background

Calothamnus quadrifidus R.Br has many traditional uses and there are few reports about its chemical and biological activities. So our aim is to isolate the triterpenoidal compounds from dichloromethane fraction (DCMF) of Calothamnus quadrifidus R.Br leaves and in addition to evaluate the antibacterial activity of the isolated compounds.

Methods

DCMF of C. quadrifidus leaves was subjected to different chromatographic techniques to isolate pure triterpenoidal compounds which were identified using different chemical and spectroscopic techniques. Antibacterial activities of the isolated compounds were evaluated using agar well diffusion method while minimum inhibitory concentration was assessed by microtiter plate assay method.

Results

Five compounds were isolated and they were betulinic acid (1), ursolic acid (2), 3-acetyl-23-hydroxy betulinic acid (3), 2,23-dihydroxy betulinic acid (4) and 2,21,23-trihydroxy betulinic acid (5) were isolated from DCMF of C. quadrifidus leaves for the first time. Compounds 4 and 5 showed strong antibacterial activity against S. typhimurium while compound 4, 5 and 3, 4 exhibits moderate effect against E.coli and S. aureus respectively.

Conclusion

Pure triterpenoidal compounds isolated from C. quadrifidus leaves showed antibacterial activities in different strengths.

Phytochemical Study of Aerial Parts of Leea asiatica

Leea asiatica (L.) Ridsdale (Leeaceae) is found in tropical and subtropical countries and has historically been used as a traditional medicine in local healthcare systems. Although L. asiatica extracts have been found to possess anthelmintic and antioxidant-related nephroprotective and hepatoprotective effects, little attention has been paid toward the investigation of phytochemical constituents of this plant. In the current study, phytochemical analysis of isolates from L. asiatica led to the identification of 24 compounds, including a novel phenolic glucoside, seven triterpenoids, eight flavonoids, two phenolic glycosides, four diglycosidic compounds, and two miscellaneous compounds. The phytochemical structures of the isolates from L. asiatica were elucidated using spectroscopic analyses including 1D- and 2D-NMR and ESI-Q-TOF-MS. The presence of triterpenoids and flavonoids supports the evidence for anthelmintic and antioxidative effects of L. asiatica.

Two new ursane-type nortriterpenes from Lonicera macranthoides and their iNOS-inhibitory activities

The flower buds of Lonicera macranthoides (Shan Yin-Hua), represent an important traditional Chinese medicine and food ingredient. A phytochemical investigation of the 70% EtOH extract of the flower buds of L. macranthoides resulted in the isolation of 12 triterpenoids (1-12), including two new ursane-type nortriterpenes, 2α, 24-dihydroxy-23-nor-ursolic acid (1) and 2α, 4α-dihydroxy-23-nor-ursolic acid (2). Their structures were established by multiple spectroscopic methods and comparison with literature data. All isolated compounds were evaluated for their anti-inflammatory effects in LPS-activated RAW264.7 cells. Compounds 1 and 2 exhibited inhibitory effects on iNOS at the concentration of 30 μmol·L-1.

Cytotoxic constituents from Helicteres hirsuta collected in Vietnam

Phytochemical study on the extract of Vietnamese medicinal plant Helicteres hirsuta Lour. has led to the isolation and structural elucidation of twelve secondary metabolites, 3-O-trans-caffeoylbetulinic acid (1), 3β-benzoylbetulinic acid (2), betulinic acid methyl ester (3), betulinic acid (4), lupeol (5), 4-hydroxybenzoic acid (6), 3,4-dihydroxybenzoic acid methyl ester (7), 4-hydroxy-3,5-dimethoxybenzoic acid (8), 5,8-dihydroxy-7,4'-dimethoxyflavone (9), isoscutellarein 4'-methyl ether 8-O-β-D-glucopyranoside (10), methyl caffeate (11) and stigmasterol (12). Especially, compound 2 was reported as a new natural product. Their structures were elucidated by a combination of 2D NMR and ESI-FT-ICR-MS spectroscopies. Furthermore, eight compounds were tested for their cytotoxicity against five cancer cell lines (Hela, HepG2, SK-LU-1, AGS and SK-MEL-2). The results showed that compounds (1, 3-5, 9) have moderate activities. This is the first study on the chemical constituents and their cytotoxicity of the Vietnamese Helicteres hirsuta L.

Pharmacological Properties, Molecular Mechanisms, and Pharmaceutical Development of Asiatic Acid: A Pentacyclic Triterpenoid of Therapeutic Promise

Asiatic acid (AA) is a naturally occurring aglycone of ursane type pentacyclic triterpenoids. It is abundantly present in many edible and medicinal plants including Centella asiatica that is a reputed herb in many traditional medicine formulations for wound healing and neuropsychiatric diseases. AA possesses numerous pharmacological activities such as antioxidant and anti-inflammatory and regulates apoptosis that attributes its therapeutic effects in numerous diseases. AA showed potent antihypertensive, nootropic, neuroprotective, cardioprotective, antimicrobial, and antitumor activities in preclinical studies. In various in vitro and in vivo studies, AA found to affect many enzymes, receptors, growth factors, transcription factors, apoptotic proteins, and cell signaling cascades. This review aims to represent the available reports on therapeutic potential and the underlying pharmacological and molecular mechanisms of AA. The review also also discusses the challenges and prospects on the pharmaceutical development of AA such as pharmacokinetics, physicochemical properties, analysis and structural modifications, and drug delivery. AA showed favorable pharmacokinetics and found bioavailable following oral or interaperitoneal administration. The studies demonstrate the polypharmacological properties, therapeutic potential and molecular mechanisms of AA in numerous diseases. Taken together the evidences from available studies, AA appears one of the important multitargeted polypharmacological agents of natural origin for further pharmaceutical development and clinical application. Provided the favorable pharmacokinetics, safety, and efficacy, AA can be a promising agent or adjuvant along with currently used modern medicines with a pharmacological basis of its use in therapeutics.

New ursane-type triterpenoids from Clerodendranthus spicatus

Five new ursane-type triterpenoids, spicatusoids A-E (1, 3-6), and three known ones (2, 7, and 8), and a known oleanane-type triterpenoid (9) were isolated from the aerial parts of Clerodendranthus spicatus. Their structures were elucidated by spectroscopic methods. In particular, the structure of 3 including its absolute configuration was confirmed by single-crystal X-ray diffraction analysis. Cell viability of all the compounds against rat kidney fibroblast cells (NRK-49F) with or without TGF-β1 induction and human cancer cells (HL-60, SMMC-7721, A-549, MCF-7, and SW-480) was examined by using MTT or MST assays. It was found that, with exception of 1, all the tested compounds could inhibit cell proliferation in TGF-β1 induced NRK-49F cells with compounds 2 being most active.

Biologically active xanthones from Codonopsis ovata

Five new xanthones, named coxanthones A-E (1-5), together with 21 known secondary metabolites (6-26) that include seven xanthones, five flavonoids, two steroids and seven triterpenoids were isolated from the chemically unexplored whole plant Codonopsis ovata. The structures of new metabolites were elucidated by HRMS, interpretation of NMR spectra and other spectroscopic techniques. The absolute configuration of the stereogenic centre of coxanthone B (2) was determined by electronic circular dichroism (ECD) spectroscopy. This is the first report of xanthones from the genus Codonopsis. All isolated metabolites were evaluated for cytotoxic activity by SRB assay against six human cancer cell lines A549 (lung), PC-3 (prostate), HCT-116 (colon), MCF-7 (breast), SF-295 (CNS), and MDAMB-435 (melanoma). Among the new compounds, coxanthone B (2) exhibited significant inhibitory activity against SF-295 and MDAMB-435 with IC₅₀ values of 7.0 and 15.0 μM, respectively. Coxanthone A (1) displayed cytotoxicity against A549 cell line at IC₅₀ value of 22.5 μM. Cytotoxic activity of 1-hydroxy-3,5-dimethoxyxanthone (7), swertiperenine (9) and 1,7,8-trihydroxy-3-methoxyxanthone (10) are reported here first time that exhibited the IC₅₀ values of 3.0, 5.0 and 21.0 μM against A549, MDAMB-435, and A549 cell lines, respectively. Kaempferol (13) showed most potent cytotoxic activity with an IC₅₀ values in the 1.0-2.3 μM range against all tested cancer cell lines.

New polyhydroxytriterpenoid derivatives from fruits of Terminalia chebula Retz. and their α-glucosidase and α-amylase inhibitory activity

Three new polyhydroxytriterpenoid derivatives, 23-O-neochebuloylarjungenin 28-O-β-d-glycopyranosyl ester (1), 23-O-4'-epi-neochebuloylarjungenin (2), and 23-O-galloylpinfaenoic acid 28-O-β-d-glucopyranosyl ester (17) were isolated from the fruits of Terminalia chebula Retz. along with fourteen known ones. Their structures were elucidated by 1D and 2D NMR spectroscopic data and acid hydrolysis. After evaluating for Baker's yeast α-glucosidase, rat intestinal α-glucosidase, and porcine pancreatic α-amylase inhibitory activities of all the isolated compounds, 23-O-galloylarjunolic acid (11, IC₅₀ 21.7μM) and 23-O-galloylarjunolic acid 28-O-β-d-glucopyranosyl ester (12, IC₅₀ 64.2μM) showed potent inhibitory activities against Baker's yeast α-glucosidase compared to the positive control, acarbose (IC₅₀ 174.0μM). However, all the tested compounds except for the positive control, acarbose, had no or only weak inhibitory activity against rat intestinal α-glucosidase and porcine pancreatic α-amylase.

Two New Oleanane-type Triterpenoids from Methanolyzed Saponins of Momordica cochinchinensis

Two new oleanane-type triterpenoid saponins (1 and 2) were isolated from the methanolyzed total saponins of the seeds of Momordica cochinchinensis (Lour.) Spreng, together with 16 known compounds (3—18). Their structures were elucidated on the basis of detailed spectroscopic, including ID and 2D NMR, mass spectrometric, methanolysis and LC-MS analysis. All the isolates were tested for their cytotoxic activities against five human cancer cell lines (HL-60, SMMC-7721, PANC-1, A-549, and SW-480) and the glucose uptake activity. The known compound 6 exhibited toxic effects against HL-60 with an IC50 value of 18.1 μM, while 10 showed cytotoxicity against SMMC-7721 and A-549 cell lines, with IC50 values of 34.4 and 32.8 μM, respectively. In addition, the new compound 2 showed glucose uptake activity with a glucose consumption value of 0.29 μM at 10 μM concentration.

Anti-inflammatory effect of birsonimadiol from seeds of Byrsonima crassifolia

The new compound identified as 16α,23α-dihydroxy-3β,28β,30α-triacetoxy-olean-12-ene, named birsonimadiol (BIR) was isolated from Byrsonima crassifolia seeds using activity-guided fractionation and structural elucidation was achieved based on extensive analysis of spectroscopic data. Effects of BIR on acute and chronic phases of inflamation were studied in edema induced using formaldehyde, 12-O-tetradecanoylphorbol-acetate (TPA)-induced ear edema (meloperoxidase activity), and histamine, carrageenan, cotton pellet granuloma, and adjuvant-induced arthritis. Anti-inflammatory activities of BIR were indicated based on reduction of edema levels induced in models of inflammation. Anti-inflammatory activities were also investigated in murine macrophage RAW264.7 cells. BIR suppressed production of nitric oxide (NO) and prostaglandin E₂ (PGE₂), decreased gene expression of cyclooxygenase-2 (COX-2), inhibited tumor necrosis factor (TNF)-α, and protein secretion of interleukin IL-6. Triterpene was an effective topical anti-inflammatory agent in experimental models of acute and chronic dermatitis and can be used in inflammatory disorders.

A New Taraxastane-type Triterpenoid from Cleistocalyx Operculatus

Ten known compounds including a chalcone, a long-chain alcohol, two flavonols, and six triterpenoids/steroids together with a new taraxastane-type triterpenoid, named cleistocalyxin, were isolated from the leaves of Cleistocalyx operculatus. The structure of cleistocalyxin was determined on the basis of IR, MS and NMR spectroscopic methods.

Leishmanicidal Activity of (+)-Phyllanthidine and the Phytochemical Profile of Margaritaria nobilis (Phyllanthaceae)

The effects of the Securinega alkaloid (+)-phyllanthidine on Leishmania (L.) amazonensis and the first chemical investigation of Margaritaria nobilis L.f. (Phyllanthaceae) are described. Treating the parasites with this alkaloid caused a dose-dependent reduction in promastigote growth of 67.68% (IC₅₀ 82.37 μg/mL or 353 µM) and in amastigote growth of 83.96% (IC₅₀ 49.11 μg/mL or 210 µM), together with ultrastructural alterations in the promastigotes. No cytotoxic effect was detected in mammalian cells (CC₅₀ 1727.48 µg/mL or CC₅₀ 5268 µM). Classical chromatographic techniques and spectral methods led to the isolation and identification of betulinic acid, kaempferol, corilagin, gallic acid and its methyl ester, besides (+)-phyllanthidine from M. nobilis leaves and stems. Margaritaria nobilis is another source of the small group of Securinega alkaloids, together with other Phyllanthaceae (Euphorbiaceae s.l.) species. The low toxicity to macrophages and the effects against promastigotes and amastigotes are suggestive that (+)-phyllanthidine could be a promising antileishmanial agent for treating cutaneous leishmaniasis.