Antiproliferative polycyclic polyprenylated acylphloroglucinols from Garcinia paucinervis

Bioassay-guided isolation of the stems of Garcinia paucinervis led to one new adamantane-type polycyclic polyprenylated acylphloroglucinols (PPAPs), (-)-garpauvinin A (1), and four known analogues (2-5). The structure and absolute configuration of 1 was established via spectroscopic techniques and ECD method. All the isolates displayed moderate antiproliferative activity against HL-60, PC-3 and Caco-2 human cancer cell lines with IC50 values ranging from 0.81 to 19.92 μM, and exhibited low toxicity on WPMY-1 normal human cells, showing selectivity between normal and malignant prostate cells. The biosynthetic pathways of the isolated PPAPs were proposed.

Garcinia macrophylla: a Promising Underutilized Source of Bioactive Compounds in the Amazonia - A Review

Native species from the Amazonia are still unknown or underutilized and few information about their chemical and biological properties are available in the literature. Among the underutilized plant species in the Amazonia, Garcinia macrophylla can be seen as a promising source of bioactive compounds with relevant biological properties. The stem bark and leaves were the main investigated plant parts, mainly concerning the antioxidant, antibacterial, cytotoxicity and antidiabetic properties. However, the bioactive compounds and biological properties of the edible fruits were not yet reported. Systematic investigations covering the Amazonia biome, concerning plants and vegetables as strategic resources are of paramount importance for the sustainable development of the forest. Therefore, this review gathered the available information in the literature concerning general aspects, chemical profile and biological properties of G. macrophylla, for the first time, which highlighted that systematic and robust in vitro and in vivo research, are still needed to elucidate the phytochemical profiles and associated relevant biological properties.

Cytotoxic depsidones and xanthones from Garcinia esculenta Y. H. Li

Six new compounds, including two depsidones garciculendepsidones A and B (1 and 2), one prenylated xanthone garciculenxanthone (3) and three dimeric xanthones bigarciculenxanthones A-C (4-6), were isolated from the twigs and leaves of Garcinia esculenta Y. H. Li. Their structures were elucidated based on comprehensive analyses of spectral data, including HRESIMS, 1D and 2D NMR, and ECD calculation. All the isolates were tested for their cytotoxicity against five human cancer cell lines (myeloid leukemia HL-60, lung cancer A-549 cells, hepatocellular carcinoma SMMC-7721, breast cancer MDA-MB-231 and colon cancer SW480), among them, compounds 3-5 displayed cytotoxic potential, especially garciculenxanthone (3) had the lowest IC50 value of 8.2 μm for lung cancer A-549 cells.

Cytotoxic xanthones from Garcinia pedunculata fruits

Eight previously undescribed and seven known xanthones were isolated from the fruits of Garcinia pedunculata Roxb. The structures were identified by a variety of spectroscopic methods as well as by comparison with the literature. The isolates showed appreciable cytotoxicity against three human tumor cell lines (HepG2, A549, and MCF-7). Pedunculaxanthone G exhibited inhibitory activities with IC50 values of 12.41, 16.51, and 15.45 μM against the cancer cell lines and induced cell apoptosis in HepG2 cells.

Caged Polyprenylated Xanthones in Garcinia hanburyi and the Biological Activities of Them

The previous phytochemical analyses of Garcinia hanburyi revealed that the main structural characteristic associated with its biological activity is the caged polyprenylated xanthones with a unique 4-oxatricyclo [4.3.1.03,7] dec-2-one scaffold, which contains a highly substituted tetrahydrofuran ring with three quaternary carbons. Based on the progress in research of the chemical constituents, pharmacological effects and modification methods of the caged polyprenylated xanthones, this paper presents a preliminary predictive analysis of their drug-like properties based on the absorption, distribution, metabolism, excretion and toxicity (ADME/T) properties. It was found out that these compounds have very similar pharmacokinetic properties because they possess the same caged xanthone structure, the 9,10-double bond in a,b-unsaturated ketones are critical for the antitumor activity. The author believes that there is an urgent need to seek new breakthroughs in the study of these caged polyprenylated xanthones. Thus, the research on the route of administration, therapeutic effect, structural modification and development of such active ingredients is of great interest. It is hoped that this paper will provide ideas for researchers to develop and utilize the active ingredients derived from natural products.

[A new xanthone from hulls of Garcinia mangostana and its cytotoxic activity]

Eight compounds were isolated from ethyl acetate fraction of 80% ethanol extract of the hulls of Garcinia mangostana by silica gel, Sephadex LH-20 column chromatography, as well as prep-HPLC methods. By HR-ESI-MS, MS, 1D and 2D NMR spectral analyses, the structures of the eight compounds were identified as 16-en mangostenone E(1), α-mangostin(2), 1,7-dihydroxy-2-(3-methy-lbut-2-enyl)-3-methoxyxanthone(3), cratoxyxanthone(4), 2,6-dimethoxy-para-benzoquinone(5), methyl orselinate(6), ficusol(7), and 4-(4-carboxy-2-methoxyphenoxy)-3,5-dimethoxybenzoic acid(8). Compound 1 was a new xanthone, and compound 4 was a xanthone dimer, compound 5 was a naphthoquinone. All compounds were isolated from this plant for the first time except compounds 2 and 3. Cytotoxic bioassay suggested that compounds 1, 2 and 4 possessed moderate cytotoxicity, suppressing HeLa cell line with IC_(50) va-lues of 24.3, 35.5 and 17.1 μmol·L~(-1), respectively. Compound 4 also could suppress K562 cells with an IC_(50) value of 39.8 μmol·L~(-1).

Isolation and antihyperglycemic effects of garcibractinols A-H, intricate polycyclic polyprenylated acylphloroglucinols from the fruits of Garcinia bracteata

Eight previously undescribed polycyclic polyprenylated acylphloroglucinols (PPAPs) were isolated from the fruits of Garcinia bracteata and named garcibractinols A-H. Garcibractinols A-F (compounds 1-6) were bicyclic polyprenylated acylphloroglucinols (BPAPs) sharing a rare bicyclo[4.3.1]decane core. On the other hand, garcibractinols G and H (compounds 7 and 8) shared an unprecedented BPAP skeleton bearing a 9-oxabicyclo[6.2.1]undecane core. The structures andabsolute configurations of compounds 1-8 were determined by spectroscopic analysis,single-crystal X-ray diffraction analysis, and quantum chemical calculation. The breakage of the C-3/C-4 linkage through the retro-Claisen reaction was a key step in the biosynthesis of compounds 7 and 8. The antihyperglycemic effects of the eight compounds were evaluated in insulin-resistant HepG2 cells. At a concentration of 10 μM, compounds 2 and 5-8 significantly increased the glucose consumption in the HepG2 cells. Furthermore, compound 7 was more effective than metformin (which was used as a positive control) in promoting glucose consumption in the cells. The findings of this study suggest that compounds 2 and 5-8 have anti-diabetic effects.

Garcowacinols A-J, cytotoxic polyprenylated benzoylphloroglucinol derivatives from the twigs of Garcinia cowa

Ten undescribed polyprenylated benzoylphloroglucinol derivatives named garcowacinols A‒J (1-10) and four known analogues (11-14) were isolated from the twigs of Garcinia cowa. Their structures were determined by spectroscopic data analysis (1D and 2D NMR and HRESIMS), and their absolute configurations were established based on NOESY and ECD data. All isolated compounds were evaluated for their cytotoxicity against five types of human cancer cells (KB, HeLa S3, MCF-7, Hep G2, and HT-29) as well as Vero cells by MTT colorimetric assay. Garcowacinol C was significantly active against all the five cancer cells with IC50 values in the range of 0.61-9.50 μM. Selective proliferative inhibitions were observed on garcowacinol F and 7-epiclusianone against KB cells, and guttiferone Q toward MCF-7 cells with IC50 values less than 10 μM.

Cytotoxic Polyprenylated Benzoylphloroglucinol Derivatives from the Branches of Garcinia schomburgkiana

Five undescribed polyprenylated benzoylphloroglucinol derivatives (1:  - 5: ), named garschomcinols A - E, and five known analogues (6:  - 10: ) were isolated from the branches of Garcinia schomburgkiana. Their structures were determined on the basis of 1D and 2D NMR and HRESIMS analyses. The absolute configuration of the bicyclo [3.3.1]nonane core structure of the polyprenylated benzoylphloroglucinols was assigned by comparison of its experimental electronic circular dichroism data with that of related compounds. All isolated compounds were evaluated for their cytotoxicity in vitro against five cancer cell lines. Compound 6: showed potent cytotoxicity against five cancer cell lines including KB, HeLa S3, HT-29, MCF-7, and Hep G2 with IC₅₀ values in the range of 5.05 - 7.03 µM.

A Comprehensive Review of the Phytochemical and Pharmacological Potential of an Evergreen Plant Garcinia cowa

Garcinia cowa of the Clusiaceae family, native to South-East Asia used in traditional medicine. It has antipyretic, antimicrobial, and many other biological activities. In this review, a thorough study of this plant's chemical constituents and pharmacological and therapeutic effects was conducted from the research articles from PubMed, Science Direct, Google Scholar, and Scopus from 1977 to 2022. Reported secondary metabolites are enriched with xanthones, phloroglucinols, depsidones, steroids, etc. α-mangostin, β-mangostin, cowaxanthone, rubraxanthone, cowanin, norcowanin, etc. represent the major xanthones. This article discusses the relationship between the different functional groups in xanthone compounds and their bioactivity against cancer, diabetes, bacteria, leishmania, malaria, and inflammation. This review is a comprehensive compendium of major bioactive molecules and its implication for human disease.

Apoptotic effects of phenols from the twigs and leaves of Garcinia nujiangensis

In order to find potential agents for treating cancer disease in naturally occurring compounds, we conducted a systematic phytochemical investigation on the endemic species of Garcinia nujiangensis. Three new biphenyl derivatives (1-3) and one new polycyclic polyprenylated benzophenone (4), together with four known benzophenone analogues (5-8), have been isolated from the CH₂Cl₂ extract of the twigs and leaves of G. nujiangensis. Their structures were determined by detailed spectroscopic analyses and comparison with structurally related known analogues. Experimental and calculated ECD method was used to determine the absolute configuration of 1 and 4. Moreover, compounds 5-7 were isolated for the first time from this species. The cytotoxicities of the new compounds were evaluated using HL-60, HepG2, and A549 human cancer cell lines. Compound 4 showed more significant antiproliferative effects against HepG2 cells with an IC₅₀ value of 11.38 ± 0.79 μM than that of three biphenyl derivatives. The morphological features of apoptosis were evaluated in 4-treated HepG2 cells. Compound 4 effectively prevented the cell cycle progression of HepG2 cells in G₂ phase. Additionally, western blot analysis indicated that treatment of 4 on HepG2 cells led to decreased expression of anti-apoptotic Bcl-2 and pro-Caspase-3, and increased protein expression of both pro-apoptotic Bax and cleaved PARP with reference to β-actin. Overall, our results suggested that the active polycyclic polyprenylated benzophenone derivatives in the twigs and leaves of G. nujiangensis can be used as a valuable source of bioactive compounds for the pharmaceutical industry.

Polycyclic Polyprenylated Acylphloroglucinols Bearing a Lavandulyl-Derived Substituent from Garcinia xanthochymus Fruits

Many type B polycyclic polyprenylated acylphloroglucinols (PPAPs) bear a lavandulyl-derived substituent, and the configurational assignment of this side chain can be difficult and sometimes leads to erroneous conclusions. In this study, 21 PPAPs, including the new xanthochymusones A-I (1-9), have been isolated from the fruits of Garcinia xanthochymus and structurally characterized. The relative configuration of the C-30 stereocenter was assigned by a combination of chemical transformations, ¹H-¹H coupling constants, conformational analysis, and NOE experiments. The configurational assignment of compound 7 indicates that the relative configuration at C-30 of PPAPs is not always the same. The absolute configurations of the new compounds were assigned by ECD and X-ray diffraction data, as well as by biosynthetic considerations. Analysis of NMR data enabled the configurational revision of garcicowins C and D. All the isolated PPAPs were tested for antiproliferative activity against three human hepatocellular carcinoma cell lines, including Huh-7, Hep 3B, and HepG2. Compounds 5 and 6, 7-epi-isogarcinol (16), and coccinone C (17) exhibited moderate antiproliferative activity. Compounds 6 and 16 induced apoptosis and inhibited cell migration in Huh-7 cells, probably through downregulating the STAT3 signaling pathway. This study provides effective methods for configurational assignments of type B PPAPs.

Garcinia gummi-gutta seeds: a novel source of edible oils

BACKGROUND

Edible oils are important for human nutrition and health. The demand for edible oils is increasing globally and the situation warrants the identification of new natural sources of oils that have been subjected to proper quality and safety evaluation. Garcinia gummi-gutta is a widely cultivated fruit crop in Kerala, south India. The fruit rinds are the useful part, while the seeds are treated as waste material. This study evaluated the composition, physico-chemical properties, and toxicity of the seed oil with a view to considering its utility in the food sector.

RESULTS

The yield of oil obtained from the seeds of Garcinia gummi-gutta through hexane extraction was 335.30 g kg^-1 . The physico-chemical parameters of the oil were determined through nuclear magnetic resonance (NMR) studies. The values agree well with those of conventional edible oils. Stearic acid, a saturated fatty acid, was identified as the main component (55.39%) followed by monounsaturated oleic acid (40.22%) through gas chromatography-mass spectrometry (GC-MS) analysis of fatty acid methyl esters (FAMEs). Preliminary in vivo acute oral toxicity studies and acute dermal toxicity studies on female Wistar rats, and dermal irritation studies on New Zealand white male rabbits showed no morbidity, mortality, appreciable change in the bodyweight, or clinical signs of dermal responses.

CONCLUSIONS

The results suggest that the seeds of G. gummi-gutta are a rich source of edible oil. The presence of stearic acid, a stable fatty acid, as the major constituent suggests that the oil could be suitable for use in value-added food products such as chocolates. Preliminary toxicological studies also recommend the use of the oil in the food and cosmetics sectors. © 2021 Society of Chemical Industry.

Neuraminidase Inhibitor of Garcinia atroviridis L. Fruits and Leaves Using Partial Purification and Molecular Characterization

Neuraminidase (NA) is an enzyme that prevents virions from aggregating within the host cell and promotes cell-to-cell spread by cleaving glycosidic linkages to sialic acid. The best-known neuraminidase is the viral neuraminidase, which present in the influenza virus. Thus, the development of anti-influenza drugs that inhibit NA has emerged as an important and intriguing approach in the treatment of influenza. Garcinia atroviridis L. (GA) dried fruits (GAF) are used commercially as seasoning and in beverages. The main objective of this study was to identify a new potential neuraminidase inhibitor from GA. A bioassay-guided fractionation method was applied to obtain the bioactive compounds leading to the identification of garcinia acid and naringenin. In an enzyme inhibition study, garcinia acid demonstrated the highest activity when compared to naringenin. Garcinia acid had the highest activity, with an IC₅₀ of 17.34–17.53 µg/mL or 91.22–92.21 µM against Clostridium perfringens-NA, and 56.71–57.85 µg/mL or 298.32–304.31 µM against H1N1-NA. Based on molecular docking results, garcinia acid interacted with the triad arginine residues (Arg118, Arg292, and Arg371) of the viral neuraminidase, implying that this compound has the potential to act as a NA enzyme inhibitor.

Structural Optimization and Improving Antitumor Potential of Moreollic Acid from Gamboge

Moreollic acid, a caged-tetraprenylated xanthone from Gamboge, has been indicated as a potent antitumor molecule. In the present study, a series of moreollic acid derivatives with novel structures were designed and synthesized, and their antitumor activities were determined in multifarious cell lines. The preliminary screening results showed that all synthesized compounds selectively inhibited human colon cancer cell proliferation. TH12-10, with an IC50 of 0.83, 1.10, and 0.79 μM against HCT116, DLD1, and SW620, respectively, was selected for further antitumor mechanism studies. Results revealed that TH12-10 effectively inhibited cell proliferation by blocking cell-cycle progression from G1 to S. Besides, the apparent structure-activity relationships of target compounds were discussed. To summarize, a series of moreollic acid derivatives were discovered to possess satisfactory antitumor potentials. Among them, TH12-10 displays the highest antitumor activities against human colon cancer cells, in which the IC50 values in DLD1 and SW620 are lower than that of 5-fluorouracil.

Kolaflavanone, a biflavonoid derived from medicinal plant Garcinia, is an inhibitor of mitotic kinesin Eg5

Mitotic kinesin Eg5 remains a validated target in antimitotic therapy because of its essential role in the formation and maintenance of bipolar mitotic spindles. Although numerous Eg5 inhibitors of synthetic origin are known, only a few inhibitors derived from natural products have been reported. In our study, we focused on identifying novel Eg5 inhibitors from medicinal plants, particularly Garcinia species. Herein, we report the inhibitory effect of kolaflavanone (KLF), a Garcinia biflavonoid, on the ATPase and microtubule-gliding activities of mitotic kinesin Eg5. Additionally, we showed the interaction mechanism between Eg5 and KLF via in vitro and in silico analyses. The results revealed that KLF inhibited both the basal and microtubule-activated ATPase activities of Eg5. The inhibitory mechanism is allosteric, without a direct competition with adenosine-5'-diphosphate for the nucleotide-binding site. KLF also suppressed the microtubule gliding of Eg5 in vitro. The Eg5-KLF model obtained from molecular docking showed that the biflavonoid exists within the α2/α3/L5 (α2: Lys111-Glu116 and Ile135-Asp149, α3: Asn206-Thr226; L5: Gly117-Gly134) pocket, with a binding pose comparable to known Eg5 inhibitors. Overall, our data suggest that KLF is a novel allosteric inhibitor of mitotic kinesin Eg5.

Protective effect of standardised fruit extract of Garcinia cowa Roxb. ex Choisy against ethanol induced gastric mucosal lesions in Wistar rats

BACKGROUND AND AIM

The fruit of Garcinia is a rich and valuable source of bioactive compounds and is traditionally used for treating wounds and ulcers. The present study was carried out to investigate the protective effect of chromatographically standardized fruit extract of Garcinia cowa (GCE) on ethanol-induced gastric lesions in rats and its possible mechanisms.

METHODS

The effect of GCE (200 and 400 mg/kg body weight) was evaluated by determining various gastric ulcer parameters like gastric wall mucus, non-protein sulfhydryls (NP-SH) content, microvascular permeability, endogenous antioxidant enzyme, and gastric histopathological study.

RESULTS AND CONCLUSIONS

Oral administration of GCE at doses of 200 and 400 mg/kg exhibited significant (p < .01) dose-dependent inhibition of ulcer index by 18.94-44.02%, respectively. Pre-treatment of rats with GCE (400 mg/kg) significantly restored the depleted gastric wall mucus level by 34.09% and NP-SH content by 33.35% induced by ethanol administration. In addition, GCE (400 mg/kg) showed a significant decrease in microvascular permeability of Evans Blue by 47.43%, rationalizing its protective effect. Furthermore, a significant increase in oxidative enzyme levels with reduction in malondialdehyde level and elevation of superoxide dismutase (SOD) activity was observed in the GCE treated group as compared to the ulcer control group. The histopathological assessment also confirmed the protective nature of GCE. HPTLC analysis showed the presence of 0.27%, 0.11% w/w gallic acid, and amentoflavone, respectively in GCE. The content of α-mangostin and xanthochymol in the G. cowa extract sample quantified by HPLC-PDA method was 0.72 and 8.46%, respectively. The results obtained indicate that the protective effect of GCE against gastric ulcers in rats through multiple actions confirmed by the reduction of oxidative stress and restoration of adhered gastric mucus, NP-SH content, and histological architecture.KEY MESSAGESEthanol is the most typical ulcerogenic agent and has been shown to extend the risk of ulcer in humans.Natural products are promising alternative medication for the development of new drugs to regulate gastrointestinal diseases.Garcinia cowa protects the gastric mucosa through multiple actions that include restoration of adhered gastric mucus and inhibition of lipid peroxidation.

Cytotoxic new caged-polyprenylated xanthonoids from Garcinia oligantha

Caged-polyprenylated xanthonoids represent a rare class of natural products. This type of compounds is mainly isolated from Genus Garcinia. Phytochemical studies on the leaves and twigs of Garcinia oligantha led to the isolation of four new caged-polyprenylated xanthonoids, oliganthone CF (1-4), and two new simple xanthones (5-6), oliganthaxanthone D and oliganthaxanthone E. Eight known other polyprenylated xanthones (7-14) including five caged-polyprenylated xanthonoids (7-11) were also isolated. Their structures were elucidated based on the analyses of extensive spectroscopic data. All the isolated compounds except for 5, 6 and 14 showed cell viability reducing effect against human lung cancer A549 cells. Compounds 1-3 were proved to be potential apoptosis inducing agents.

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).

Polycyclic polyprenylated acylphloroglucinol congeners from Garcinia yunnanensis Hu with inhibitory effect on α-hemolysin production in Staphylococcus aureus

α-Hemolysin (Hla) is an extracellular protein secreted by methicillin-resistant Staphylococcus aureus (MRSA) strains that plays a critical role in the pathogenesis of pulmonary, intraperitoneal, intramammary, and corneal infections, rendering Hla a potential therapeutic target. In this study, 10 unreported polycyclic polyprenylated acylphloroglucinol (PPAP) derivatives, garciyunnanins C-L (1-10), with diverse skeletons, were isolated from Garcinia yunnanensis Hu. The structures of these new compounds were determined by HRMS, NMR, electronic circular dichroism (ECD) calculations, single-crystal X-ray diffraction, and biomimetic transformation. Garciyunnanins C and D (1 and 2) were found to be potent Hla inhibitors in the anti-virulence efficacy evaluation against MRSA strain.

Cytotoxic and Antiangiogenetic Xanthones Inhibiting Tumor Proliferation and Metastasis from Garcinia xipshuanbannaensis

Eight prenylated xanthones including four new analogues were extracted and purified from the leaves of Garcinia xipshuanbannaensis. Multiple techniques including UV, 1D and 2D NMR, and HRESIMS were used to determine the structures of the isolated xanthones. These xanthones were evaluated for their cytotoxicity toward human cancer cells, and compound 4 exhibited activity against HeLa cells. A cytotoxic mechanism examination revealed the active compound induced cell apoptosis by arresting the cell cycle, increasing the levels of ROS, and inhibiting the expression of p-STAT3 in HeLa cells. In in vivo zebrafish experiments, compound 4 was found to block tumor proliferation and migration and have antiangiogenetic activity, and thus seems worthy of further laboratory evaluation.

Nujiangexanthone A Inhibits Cervical Cancer Cell Proliferation by Promoting Mitophagy

Nujiangexanthone A (NJXA), a bioactive component isolated from the leaves of Garcinia nujiangensis, has been reported to exhibit anti-inflammatory, antioxidant, and antitumor effects. Our previous work has shown that NJXA induced G0/1 arrest and apoptosis, thus suppressing cervical cancer cell growth. The present study provides new evidence that NJXA can induce cell death in HeLa cells by promoting mitophagy. We first identified that NJXA triggered GFP-LC3 and YFP-Parkin puncta accumulation, which are biomarkers of mitophagy. Moreover, NJXA degraded the mitochondrial membrane proteins Tom20 and Tim23 and mitochondrial fusion proteins MFN1 and MFN2, downregulated Parkin, and stabilized PINK1. Additionally, we revealed that NJXA induced lysosome degradation and colocalization of mitochondria and autophagosomes, which was attenuated by knocking down ATG7, the key regulator of mitophagy. Furthermore, since mitophagy is induced under starvation conditions, we detected the cytotoxic effect of NJXA in nutrient-deprived HeLa cells and observed better cytotoxicity. Taken together, our work contributes to the further clarification of the mechanism by which NJXA inhibits cervical cancer cell proliferation and provides evidence that NJXA has the potential to develop anticancer drugs.

Structural Revision of Guttiferone F and 30-epi-Cambogin

Guttiferone F, a natural polyprenylated polycyclic acylphloroglucinol, was originally assigned as the 30-epimer of garcinol by NMR data analyses. Conversion of guttiferone F in the presence of acid afforded its cyclized form (2a), which was previously assigned as 30-epi-cambogin. However, the absolute configurations of guttiferone F and 2a have not been determined. Reinvestigation of the structures of those two compounds, using X-ray and NMR data analyses and chemical transformation, revealed that the original assignment of the C-30 absolute configuration in guttiferone F and 2a should be inverted. Guttiferone F is indeed garcinol, and 2a, which was previously identified as 30-epi-cambogin, is cambogin.

Structure Elucidation and Confirmation of Phloroglucinols from the Roots of Garcinia dauphinensis by Comparison of Experimental and Calculated ECD Spectra and Specific Rotations

Eight phloroglucinols from Garcinia dauphinensis were recently reported to have good to moderate antiplasmodial and anticancer activities, consistent with other phloroglucinol derivatives isolated from natural sources. Chiroptical properties were previously calculated and compared to experimental data for compound 2 as a means to deduce its absolute configuration. Tentative assignments for the remaining compounds were also reported based on these data. In order to arrive at stereochemical assignments for phloroglucinols 1 and 3-8, ECD spectra and specific rotations were computed for all stereoisomers of each compound. Molecular orbital analyses were also carried out for the most energetically favorable conformers of each compound. Absolute configurations are reported for all eight phloroglucinols for the first time.

Structural Elucidation of Garcipaucinones A and B From Garcinia paucinervis Using Quantum Chemical Calculations

Two tocotrienol derivatives, garcipaucinones A (1) and B (2), and a biosynthetically related known analogue (3) were isolated from the fruit of Garcinia paucinervis. Their structures including absolute configurations were unequivocally determined by spectroscopic methods complemented with electronic circular dichroism (ECD) calculations and gauge-independent atomic orbital (GIAO) NMR calculations. Compounds 1 and 2 are the first naturally occurring tocotrienol derivatives with a 3,10-dioxatricyclo-[7.3.1.0^2,7]tridecane skeleton incorporating an unusual γ-pyrone motif. A reasonable biosynthetic pathway for formation of the two compounds is proposed. The antiproliferative and anti-inflammatory activities of compounds 1 and 2 were also evaluated.

Garcimultiflorone K from Garcinia multiflora attenuates hepatocellular carcinoma metastasis by suppressing transforming growth factor-β signaling

BACKGROUND

Transforming growth factor‑β (TGF-β) signaling is a crucial inducer of tissue fibrosis and extracellular matrix accumulation and a vital suppressor of epithelial cell proliferation and cancer metastasis. The nature of this multifunctional cytokine has prompted the development of TGF-β signaling inhibitors as therapeutic agents. Our research group has recently isolated the polyprenylated polycyclic acylphloroglucinol garcimultiflorone K (GMK) from the stems of Garcinia multiflora; GMK exhibits antiangiogenic activity in endothelial cells.

PURPOSE

In the current study, we aimed to explore the antitumor effect and detailed mechanisms of Garcimultiflorone K in hepatocellular carcinoma cells.

METHODS

Cell proliferation and viability were evaluated using the MTT assay. The migratory ability of HepG2 cells was measured using wound healing assays. The inhibitory effect of GMK against the nuclear translocation of Smad by TGF-β was assessed through immunofluorescence staining and Western blotting. To investigate TGF-β-dependent gene expression profiles upon GMK stimulation, RNA transcript levels were determined using reverse transcription polymerase chain reaction. The effects of GMK in Smad2-driven transcriptomic activities were studied using a reporter gene assay. Protein levels were detected using Western blotting.

RESULTS

Our data revealed that GMK inhibited TGF-β-induced cellular responses, including Smad protein phosphorylation, cell migration, and extracellular matrix production, during epithelial-mesenchymal transition (EMT). Mechanistic studies further demonstrated that GMK suppressed TGF-β signaling by downregulating TGF-β receptor II (TβRII).

CONCLUSION

These findings elucidate that TβRII expression in hepatic cells can be specifically suppressed by GMK to attenuate metastasis and the disease-promoting effects of EMT, representing a therapeutic approach.

Trypanosuppressive effects of Kolaviron may be associated with down regulation of Trypanothione reductase in Trypanosoma congolense infection

Trypanothione reductase is a key enzyme that upholds the redox balance in hemoflagellate protozoan parasites such as T. congolense. This study aims at unraveling the potency of Kolaviron against trypanothione reductase in T. congolense infection using Chrysin as standard. The experiment was performed using three different approaches; in silico, in vitro and in vivo. Kolaviron and Chrysin were docked against trypanothione reductase, revealing binding energies (-9.3 and -9.0 kcal/mol) and Ki of 0.211μM and 0.151μM at the active site of trypanothione reductase as evident from the observed strong hydrophobic/hydrogen bond interactions. Parasitized blood was used for parasite isolation and trypanothione reductase activity assay using standard protocol. Real-time PCR (qPCR) assay was implored to monitor expression of trypanothione reductase using primers targeting the 177-bp repeat satellite DNA in T. congolense with SYBR Green to monitor product accumulation. Kolaviron showed IC50 values of 2.64μg/ml with % inhibition of 66.78 compared with Chrysin with IC50 values of 1.86μg/ml and % inhibition of 53.80. In vivo studies following the administration of these compounds orally after 7 days post inoculation resulted in % inhibition of Chrysin (57.67) and Kolaviron (46.90). Equally, Kolaviron relative to Chrysin down regulated the expression trypanothione reductase gene by 1.352 as compared to 3.530 of the infected group, in clear agreement with the earlier inhibition observed at the fine type level. Overall, the findings may have unraveled the Kolaviron potency against Trypanosoma congolense infection in rats.

Garciesculenxanthone B induces PINK1-Parkin-mediated mitophagy and prevents ischemia-reperfusion brain injury in mice

Mitophagy is a selective form of autophagy involving the removal of damaged mitochondria via the autophagy-lysosome pathway. PINK1-Parkin-mediated mitophagy is one of the most important mechanisms in cardiovascular disease, cerebral ischemia-reperfusion (I/R) injury, and neurodegenerative diseases. In this study we conducted an image-based screening in YFP-Parkin HeLa cells to discover new mitophagy regulators from natural xanthone compounds. We found that garciesculenxanthone B (GeB), a new xanthone compound from Garcinia esculenta, induced the formation of YFP-Parkin puncta, a well known mitophagy marker. Furthermore, treatment with GeB dose-dependently promoted the degradation of mitochondrial proteins Tom20, Tim23, and MFN1 in YFP-Parkin HeLa cells and SH-SY5Y cells. We revealed that GeB stabilized PINK1 and triggered Parkin translocation to the impaired mitochondria to induce mitophagy, and these effects were abolished by knockdown of PINK1. Finally, in vivo experiments demonstrated that GeB partially rescued ischemia-reperfusion-induced brain injury in mice. Taken together, our findings demonstrate that the natural compound GeB can promote the PINK1-Parkin-mediated mitophagy pathway, which may be implicated in protection against I/R brain injury.

In Vivo Screening of Xanthones from Garcinia oligantha Identified Oliganthin H as a Novel Natural Inhibitor of Convulsions

Epilepsy is a chronic neurological disorder, characterized by recurrent, spontaneous, and transient seizures, and affects more than 70 million people worldwide. Although two dozen antiepileptic drugs (AEDs) are approved and available in the market, seizures remain poorly controlled in one-third of epileptic patients who are suffering from drug resistance or various adverse effects. Recently, the xanthone skeleton has been regarded as an attractive scaffold for the discovery and development of emerging anticonvulsants. We had isolated several dihydroxanthone derivatives previously, including oliganthin H, oliganthin I, and oliganthin N, whose structures were similar and delicately elucidated by spectrum analysis or X-ray crystallographic data, from extracts of leaves of Garcinia oligantha. These xanthone analogues were evaluated for anticonvulsant activity, and a novel xanthone, oliganthin H, has been identified as a sound and effective natural inhibitor of convulsions in zebrafish in vivo. A preliminary structure-activity relationship analysis on the relationship between structures of the xanthone analogues and their activities was also conducted. Oliganthin H significantly suppressed convulsant behavior and reduced to about 25% and 50% of PTZ-induced activity, in 12.5 and 25 μM treatment groups (P < 0.01 and 0.001), respectively. Meanwhile, it reduced seizure activity, velocity, seizure duration, and number of bursts in zebrafish larvae (P < 0.05). Pretreatment of oliganthin H significantly restored aberrant induction of gene expressions including npas4a, c-fos, pyya, and bdnf, as well as gabra1, gad1, glsa, and glula, upon PTZ treatment. In addition, in silico analysis revealed the stability of the oliganthin H-GABAA receptor complex and their detailed binding pattern. Therefore, direct interactions with the GABAA receptor and involvement of downstream GABA-glutamate pathways were possible mechanisms of the anticonvulsant action of oliganthin H. Our findings present the anticonvulsant activity of oliganthin H, provide a novel scaffold for further modifications, and highlight the xanthone skeleton as an attractive and reliable resource for the development of emerging AEDs.

Gambogic Acid as a Candidate for Cancer Therapy: A Review

Gambogic acid (GA), a kind of dry resin secreted by the Garcinia hanburyi tree, is a natural active ingredient with various biological activities, such as anti-cancer, anti-inflammatory, antioxidant, anti-bacterial effects, etc. An increasing amount of evidence indicates that GA has obvious anti-cancer effects via various molecular mechanisms, including the induction of apoptosis, autophagy, cell cycle arrest and the inhibition of invasion, metastasis, angiogenesis. In order to improve the efficacy in cancer treatment, nanometer drug delivery systems have been employed to load GA and form micelles, nanoparticles, nanofibers, and so on. In this review, we aim to offer a summary of chemical structure and properties, anti-cancer activities, drug delivery systems and combination therapy of GA, which might provide a reference to promote the development and clinical application of GA.

Medicinal Potential of Garcinia Species and Their Compounds

Garcinia is a genus of Clusiaceae, distributed throughout tropical Asia, Africa, New Caledonia, Polynesia, and Brazil. Garcinia plants contain a broad range of biologically active metabolites which, in the last few decades, have received considerable attention due to the chemical compositions of their extracts, with compounds which have been shown to have beneficial effects in several diseases. Our work had the objective of reviewing the benefits of five Garcinia species (G. brasiliensis, G. gardneriana, G. pedunculata, G. cambogia, and G. mangstana). These species provide a rich natural source of bioactive compounds with relevant therapeutic properties and anti-inflammatory effects, such as for the treatment of skin disorders, wounds, pain, and infections, having demonstrated antinociceptive, antioxidant, antitumoral, antifungal, anticancer, antihistaminic, antiulcerogenic, antimicrobial, antiviral, vasodilator, hypolipidemic, hepatoprotective, nephroprotective, and cardioprotective properties. This demonstrates the relevance of the genus as a rich source of compounds with valuable therapeutic properties, with potential use in the prevention and treatment of nontransmissible chronic diseases.

A Bottom-Up Synthesis Approach to Silver Nanoparticles Induces Anti-Proliferative and Apoptotic Activities Against MCF-7, MCF-7/TAMR-1 and MCF-10A Human Breast Cell Lines

A bottom-up approach for synthesizing silver nanoparticles (AgNPs-GA) phytomediated by Garcinia atroviridis leaf extract is described. Under optimized conditions, the AgNPs-GA were synthesized at a concentration of 0.1 M silver salt and 10% (w/v) leaf extract, 1:4 mixing ratio of reactants, pH 3, temperature 32 °C and 72 h reaction time. The AgNPs-GA were characterized by various analytical techniques and their size was determined to be 5–30 nm. FTIR spectroscopy indicates the role of phenolic functional groups in the reduction of silver ions into AgNPs-GA and in supporting their subsequent stability. The UV-Visible spectrum showed an absorption peak at 450 nm which reflects the surface plasmon resonance (SPR) of AgNPs-GA and further supports the stability of these biosynthesized nanoparticles. SEM, TEM and XRD diffractogram analyses indicate that AgNPs-GA were spherical and face-centered-cubic in shape. This study also describes the efficacy of biosynthesized AgNPs-GA as anti-proliferative agent against human breast cancer cell lines, MCF-7 and MCF-7/TAMR-1. Our findings indicate that AgNPs-GA possess significant anti-proliferative effects against both the MCF-7 and MCF-7/TAMR-1 cell lines, with inhibitory concentration at 50% (IC₅₀ values) of 2.0 and 34.0 µg/mL, respectively, after 72 h of treatment. An induction of apoptosis was evidenced by flow cytometry using Annexin V-FITC and propidium iodide staining. Therefore, AgNPs-GA exhibited its anti-proliferative activity via apoptosis on MCF-7 and MCF-7/TAMR-1 breast cancer cells in vitro. Taken together, the leaf extract from Garcinia atroviridis was found to be highly capable of producing AgNPs-GA with favourable physicochemical and biological properties.

Targeting MHC Regulation Using Polycyclic Polyprenylated Acylphloroglucinols Isolated from Garcinia bancana

Modulation of major histocompatibility complex (MHC) expression using drugs has been proposed to control immunity. Phytochemical investigations on Garcinia species have allowed the isolation of bioactive compounds such as polycyclic polyprenylated acylphloroglucinols (PPAPs). PPAPs such as guttiferone J (1), display anti-inflammatory and immunoregulatory activities while garcinol (4) is a histone acetyltransferases (HAT) p300 inhibitor. This study reports on the isolation, identification and biological characterization of two other PPAPs, i.e., xanthochymol (2) and guttiferone F (3) from Garcinia bancana, sharing structural analogy with guttiferone J (1) and garcinol (4). We show that PPAPs 1-4 efficiently downregulated the expression of several MHC molecules (HLA-class I, -class II, MICA/B and HLA-E) at the surface of human primary endothelial cells upon inflammation. Mechanistically, PPAPs 1-4 reduce MHC proteins by decreasing the expression and phosphorylation of the transcription factor STAT1 involved in MHC upregulation mediated by IFN-γ. Loss of STAT1 activity results from inhibition of HAT CBP/p300 activity reflected by a hypoacetylation state. The binding interactions to p300 were confirmed through molecular docking. Loss of STAT1 impairs the expression of CIITA and GATA2 but also TAP1 and Tapasin required for peptide loading and transport of MHC. Overall, we identified new PPAPs issued from Garcinia bancana with potential immunoregulatory properties.

Antiproliferative Activity and Antioxidant Potential of Extracts of Garcinia gardneriana

The aim of this study was to evaluate the antiproliferative activity, the antioxidant potential, and the chemical profile obtained from the whole fruit and from leaves of Garcinia gardneriana, a fruit tree from Brazilian Cerrado. To determine in vitro antiproliferative activity, the following neoplastic cell lines were considered, along with an immortalized nontumor cell line. The antioxidant potential was determined, and the evaluation of antiradical air activity was performed. The levels of vitamin C and carotenoids were determined. The chemical profile was analyzed by high-performance liquid chromatography coupled to a diode array detector and a mass spectrometer using electrospray ionization interface. The chloroform fraction of the leaf showed antioxidant activity. The vitamin C content had lower values in fruits and higher in leaves. The content of carotenoids for fruits and leaves was expressive. The ethanolic extract and the hexane and chloroform fractions of fruits were active in all neoplastic lines tested. The leaves showed cytotoxic activity in the hexane fraction in the breast carcinoma line. The analysis of data obtained verified the presence of dimers, monomers, and tetramers of hexoses, polycarboxylic acids, xanthones, flavonoids, biflavonoids, and benzophenones.

Structural Revision of Garcinielliptin Oxide and Garcinielliptone E

Previously, Lin et al. reported the isolation and structural determination of two triterpenoids, garcinielliptin oxide (GO) and garcinielliptone E (GE). Their unusual structural features, which remained unparalleled in subsequent decades despite the intervening discovery of hundreds of other polycyclic polyprenylated acylphloroglucinols (PPAPs), caused us to question the originally assigned structures, so GO was reisolated from Garcinia subelliptica, and its NMR spectra were reacquired. In this Note, we revise the structures of GO and the related GE via NMR analysis, biosynthetic considerations, and chemical conversion. Garcinielliptone T, a new PPAP, was also isolated and characterized. GO exhibited weak inhibitory activity against acetylcholinesterase with an IC₅₀ value of 20.7 μM.

Anti-Neuraminidase Bioactives from Manggis Hutan (Garcinia celebica L.) Leaves: Partial Purification and Molecular Characterization

The neuraminidase enzyme (NA) from the influenza virus is responsible for the proliferation and infections of the virus progeny, prompting several efforts to discover and optimize effective neuraminidase inhibitors. The main aim of this study is to discover a new potential neuraminidase inhibitor that comes from Garcinia celebica leaves (GCL). The bioassay-guided isolation method was performed to obtain lead compounds. The binding interaction of the isolated compounds was predicted by using molecular docking studies. Friedeline (GC1, logP > 5.0), two lanastone derivatives (methyl-3α,23-dihydroxy-17,14-friedolanstan-8,14,24-trien-26-oat (GC2) and 24E-3a,9,23-trihydroxy-17,14-friedolanostan-14,24-dien-26-oate (GC3) with LogP > 5.0) and catechin (GC4, LogP = 1.4) were identified. The inhibitory potency of these four compounds on NA from C. perfringens and H₁N₁ was found to be as follows: GC4 > GC2 > GC3 > GC1. All compounds exhibited higher inhibitory activity towards C. perfringens NA compared to H₁N₁ NA. From the molecular docking results, GC4 favorably docked and interacted with Arg118, Arg371, Arg292, Glu276 and Trp178 residues, whilst GC2 interacted with Arg118, Arg371, Arg292, Ile222, Arg224 and Ser246. GC3 interacted with Tyr406 only. GC4 had potent NA inhibition with free energy of binding of −12 kcal/mol. In the enzyme inhibition study, GC4 showed the highest activity with an IC₅₀ of 60.3 µM and 91.0 µM for C. perfringens NA and H₁N₁ NA—respectively.

Phloroglucinol Benzophenones and Xanthones from the Leaves of Garcinia cowa and Their Nitric Oxide Production and α-Glucosidase Inhibitory Activities

Five new compounds-two phloroglucinol benzophenones, garciniacowones F (1) and G (2), and three xanthones, garciniacowones H (3), I (4), and J (5)-together with seven known xanthones (6-12) were isolated from the fresh leaves of Garcinia cowa. Their structures were elucidated by detailed analysis of NMR and MS data. Compounds 1 and 2 are phloroglucinol benzophenones containing a polyprenylated bicyclo[3.3.1]nonane ring system, while compounds 3-5 are rare xanthones having farnesyl (3 and 5) and geranylgeranyl (5) units at C-8. Compounds 1, 3, 4, 7, 8, and 10 exhibited inhibitory effects on NO production in LPS-induced RAW264.7 macrophage cells with IC₅₀ values ranging from 5.4 to 18.6 μM. Compounds 4 and 8 had α-glucosidase inhibitory activities with IC₅₀ values of 15.4 and 11.4 μM, respectively, which were more potent than that of the acarbose control.

Physiological and Metabolic Effects of Yellow Mangosteen (Garcinia dulcis) Rind in Rats with Diet-Induced Metabolic Syndrome

Metabolic syndrome is a cluster of disorders that increase the risk of cardiovascular disease and diabetes. This study has investigated the responses to rind of yellow mangosteen (Garcinia dulcis), usually discarded as waste, in a rat model of human metabolic syndrome. The rind contains higher concentrations of phytochemicals (such as garcinol, morelloflavone and citric acid) than the pulp. Male Wistar rats aged 8-9 weeks were fed either corn starch diet or high-carbohydrate, high-fat diet for 16 weeks, which were supplemented with 5% freeze-dried G. dulcis fruit rind powder during the last 8 weeks. We characterised metabolic, cardiovascular, liver and gut microbiota parameters. High-carbohydrate, high-fat diet-fed rats developed abdominal obesity, hypertension, increased left ventricular diastolic stiffness, decreased glucose tolerance, fatty liver and reduced Bacteroidia with increased Clostridia in the colonic microbiota. G. dulcis fruit rind powder attenuated these changes, improved cardiovascular and liver structure and function, and attenuated changes in colonic microbiota. G. dulcis fruit rind powder may be effective in metabolic syndrome by appetite suppression, inhibition of inflammatory processes and increased fat metabolism, possibly related to changes in the colonic microbiota. Hence, we propose the use of G. dulcis fruit rind as a functional food to ameliorate symptoms of metabolic syndrome.

Garcimultiflorone K inhibits angiogenesis through Akt/eNOS- and mTOR-dependent pathways in human endothelial progenitor cells

Background Garcimultiflorone K is a novel polyprenylated polycyclic acylphloroglucinol isolated from the stems of Garcinia multiflora that exhibits promising anti-angiogenic activity in human endothelial progenitor cells (EPCs). Purpose This study sought to determine the underlying anti-angiogenic mechanisms and pharmacological properties of garcimultiflorone K. Methods We examined the anti-angiogenic effects of garcimultiflorone K and its mechanisms of action using in vitro EPC models and in vivo zebrafish embryos. Results EPCs proliferation, migration, differentiation and capillary-like tube formation were effectively and concentration-dependently inhibited by garcimultiflorone K without any signs of cytotoxicity. Our investigations revealed that garcimultiflorone K suppressed EPCs angiogenesis through Akt, mTOR, p70S6K, and eNOS signaling cascades. Notably, garcimultiflorone K dose-dependently impeded angiogenesis in zebrafish embryos. Conclusion Our data demonstrate the anti-angiogneic effects of garcimultiflorone K in both in vitro and in vivo models. Garcimultiflorone K appears to have potential in the treatment of angiogenesis-related diseases.

Garcinol and Related Polyisoprenylated Benzophenones as Topoisomerase II Inhibitors: Biochemical and Molecular Modeling Studies

Garcinol, a polyisoprenylated benzophenone isolated from Garcinia genus, has been reported to inhibit eukaryotic topoisomerase I and topoisomerase II at concentrations comparable to that of etoposide (∼25-100 μM). With the aim to clarify the underlying molecular mechanisms by which garcinol inhibits human topoisomerase IIα and topoisomerase IIβ, biochemical assays along with molecular docking and molecular dynamics studies were carried out on garcinol and six congeners. The biochemical results revealed that garcinol derivatives appear to act as catalytic inhibitors of topoisomerase II and to inhibit ATP hydrolysis by topoisomerase II via some form of mixed inhibition. The computational investigation identified the structural elements responsible for binding to the biological target and also provided information for the eventual design of more selective and potent analogues. Collectively, our data suggest that garcinol-type agents may bind to the DNA binding surface and/or ATP domain of type II topoisomerases to antagonize function.

Simultaneous Identification and Quantification of Three Xanthones and Two Polyisoprenylated Benzophenones in Eight Indian Garcinia Species Using a Validated UHPLC-PDA Method

Background: Xanthones and polyisoprenylated benzophenones (PIBs) are two important classes of plant secondary metabolites with a wide range of bioactivities. Garcinia species synthesize numerous xanthones and PIBs. As per the literature, no data claiming simultaneous identification and quantification of three xanthones, α-mangostin, β-mangostin, γ-mangostin, and two PIBs, xanthochymol, isoxanthochymol, were found. Methods: A validated ultra-HPLC (UHPLC)-photodiode array (PDA) method for the simultaneous identification and quantification of five compounds in different extracts of eight Indian Garcinia species was developed. The compounds were separated on a Waters ACQUITY™ UPLC H-Class column using a mobile phase consisting of solvents 0.1% formic acid in water (A) and methanol (B) in gradient elution mode. The total run time was 9 min. Results: From fruit rinds of eight Indian Garcinia species, namely Garcinia cambogia, G. cowa, G. indica, G. loniceroides, G. mangostana, G. morella, G. pedunculata, and G. xanthochymus, extracts were prepared using solvents of varying polarity. These extracts were analyzed for five biologically important compounds, namely α-mangostin, β-mangostin, γ-mangostin, xanthochymol, and isoxanthochymol. The results revealed that there is a wide variation in concentration of these compounds in extracts of Garcinia species. Conclusions: The developed and validated UHPLC-PDA method could be used for simultaneous identification and quantification of these five compounds for bioprospection of other Garcinia species.

Tetrandraxanthones A-I, Prenylated and Geranylated Xanthones from the Stem Bark of Garcinia tetrandra

Nine new xanthones, tetrandraxanthones A-I (1-9), and 22 known xanthones (10-31) were isolated from Garcinia tetrandra stem bark. The structures of 1-9 were characterized through detailed spectroscopic analysis, including HRESIMS and 2D NMR data. Among the compounds tested for their cytotoxicity, 26 showed significant cytotoxic effects against five human cancer cell lines, including MCF-7, HT-29, KB, Hep G2, and HeLa S3, with IC₅₀ values in the range of 1.6-3.4 μM, while 10 and 11 were cytotoxic against the MCF-7, HeLa S3, and KB cell lines, with IC₅₀ values of 4.3-9.0 μM.

Cytotoxic Prenylated Xanthones from the Leaves of Garcinia bracteata

Six new prenylated xanthones (1: -6: ) and seventeen known xanthones were isolated from extracts of Garcinia bracteata leaves. Their structures were determined by extensive NMR and MS spectroscopic data analysis. The inhibitory activities of the isolates were assayed on HeLa, A549, PC-3, HT-29, and WPMY-1 cell lines. Compounds 1: and 15: -17: showed moderate inhibitory effects on tumor cell growth, with IC₅₀s ranging from 3.7 to 14.7 µM.

DQF J-RES NMR: Suppressing the singlet signals for improving the J-RES spectra from complex mixtures

Two-dimensional J-RESolved spectroscopy (J-RES) finds routine use in metabolomics for reducing signal overlap as it separates chemical shift and multiplet information along two frequency axes. However, only magnitude mode of the experiment is practical which prevents exploitation of its full resolving power. Tailing from high-intensity metabolite peaks often obscure nearby low-intensity metabolite peaks which leads to ambiguity in assignment of metabolites. Absorptive mode J-RES spectroscopy offers better-resolving power but comes at the cost of either sensitivity or complicated post-processing. Quite often for certain complex mixtures such as bio-fluids some components of the mixture display intense singlet signals which dominate the whole spectrum resulting in less reliable detection of weaker metabolite signals. Multi-frequency presaturation could suppress these intense singlets but will also remove the useful weaker multiplet peaks which are either totally eclipsed with the intense singlets or very close in frequency. We show that by using a double quantum filter (DQF) in magnitude mode J-RES technique, the intensity of the strong singlet metabolite peaks can be reduced relative to the intensity of the sparsely present multiplet metabolite signals. This approach leads to the identification of many weak intensity multiplet peaks which are otherwise undetected due to their overlap with intense singlet peaks in regular J-RES as well as 1D ¹H spectra. Although the improved intensity of most of the weaker peaks relative to the strong singlet peaks is observed, some multiplets can disappear due to the delay-dependent modulation of the signals by the DQF. A few DQF J-RES spectra recorded with different DQF delays, therefore, produce better assignment when analyzed together. The technique is demonstrated on a mixture of eight compounds, human urine, and plant extract samples.

Phloroglucinols from the Roots of Garcinia dauphinensis and Their Antiproliferative and Antiplasmodial Activities

Garcinia dauphinensis is a previously uninvestigated endemic plant species of Madagascar. The new phloroglucinols dauphinols A-F and 3'-methylhyperjovoinol B (1-7) and six known phloroglucinols (8-13) together with tocotrienol 14 and the three triterpenoids 15-17 were isolated from an ethanolic extract of G. dauphinensis roots using various chromatographic techniques. The structures of the isolated compounds were elucidated by NMR, MS, optical rotation, and ECD data. Theoretical ECD spectra and specific rotations for 2 were calculated and compared to experimental data in order to assign its absolute configuration. Among the compounds tested, 1 showed the most promising growth inhibitory activity against A2870 ovarian cancer cells, with IC50 = 4.5 ± 0.9 μM, while 2 had good antiplasmodial activity against the Dd2 drug-resistant strain of Plasmodium falciparum, with IC50 = 0.8 ± 0.1 μM.

Garcixanthone A, a new cytotoxic xanthone from the pericarps of Garcinia mangostana

A new prenylated xanthone, garcixanthone A (5), together with eight known compounds, mangostanaxanthones I (1) and II (2), garcinone E (3), β-mangostin (4), 8-hydroxycudraxanthone G (6), garcinone C (7), cudraxanthone G (8), and (-)-epicatechin (9) were isolated from the EtOAc-soluble fraction of the air-dried pericarps of Garcinia mangostana (family Clusiaceae). Their structures were verified on the basis of spectroscopic data interpretation as well as comparison with the literature. The cytotoxic and antimicrobial activities of the new compound were assessed using sulforhodamine B (SRB) and agar disk diffusion assays, respectively. Compound 5 showed significant cytotoxic potential against epithelial lung carcinoma (A549) and breast carcinoma (MCF7) cell lines with IC₅₀s 3.0 and 4.2 μM, respectively, compared to doxorubicin (0.74 and 0.41 μM, respectively).

Construction and Application of a Database for a Five-Dimensional Identification of Natural Compounds in Garcinia Species by Means of UPLC-ESI-TWIMS-TOF-MS: Introducing Gas Phase Polyphenol Conformer Drift Time Distribution Intensity Ratios

Thirty-four reference compounds from G. buchananii were analyzed by means of UPLC-ESI-IMS-TOF-MS to build a database consisting of retention time, accurate m/ z of precursors and fragment ions, and rotationally averaged collision cross-sectional area (CCS). The CCS value of six selected compounds analyzed in bark extract in different concentrations and solvent systems showed excellent intra- and interday precision (RSD ≤ 0.9%). The established database was applied on different organs of G. buchananii as well as G. kola, G. mangostana, and G. cambogia enabling a fast and reliable identification of these natural bioactives. For several compounds, more than one drift time species could be highlighted, which we propose to be hydrogen bond stabilized rotational isomers transferred from solution to gas phase. We used all CCS values of one compound, and we propose to add also the intensity ratio of the conformers as a new and additional characteristic compound parameter in compound identification/screening/database applications to reduce dereplication and false positives and to strengthen the identification.

13C-NMR dereplication of Garcinia extracts: Predicted chemical shifts as reliable databases

Usually isolated from Garcinia (Clusiaceae) or Hypericum (Hypericaceae) species, some Polycyclic Polyprenylated AcylPhloroglucinols (PPAPs) have been recently reported as potential research tools for immunotherapy. Aiming at exploring the chemodiversity of PPAPs amongst Garcinia genus, a dereplication process suitable for such natural compounds has been developed. Although less sensitive than mass spectrometry, NMR spectroscopy is perfectly reproducible and allows stereoisomers distinction, justifying the development of ¹³C-NMR strategies. Dereplication requires the use of databases (DBs). To define if predicted DBs were accurate enough as dereplication tools, experimental and predicted δ_C of natural products usually isolated from Clusiaceae were compared. The ACD/Labs commercial software allowed to predict 73% of δ_C in a 1.25 ppm range around the experimental values. Consequently, with these parameters, the major PPAPs from a Garcinia bancana extract were successfully identified using a predicted DB.

Cytotoxicity of epunctanone and four other phytochemicals isolated from the medicinal plants Garcinia epunctata and Ptycholobium contortum towards multi-factorial drug resistant cancer cells

INTRODUCTION

Resistance of cancer cells is a serious impediment to chemotherapy and several phytochemicals are active against multi-drug resistant (MDR) phenotypes. The cytotoxicity of five naturally occurring compounds: betulin (1), mundulea lactone (2), seputhecarpan A (3), seputheisoflavone (4) and epunctanone (5) was evaluated on a panel of 9 cancer cell lines including various sensitive and drug-resistant cell lines. The modes of action of compound 5 were further investigated.

METHODS

The resazurin reduction assay was used to evaluate cytotoxicity of samples and ferroptotic cell death induced by compound 5; caspase-Glo assay was used to detect the activation of caspases in CCRF-CEM leukemia cells treated with compound 5. Flow cytometry was used for cell cycle analysis in CCRF-CEM cells treated with compound 5, as well as detection of apoptotic cells by annexin V/PI staining, analysis of mitochondrial membrane potential (MMP) and measurement of reactive oxygen species (ROS).

RESULTS

Compounds 1-5 displayed cytotoxic effects in the 9 studied cancer cell lines with IC₅₀ values below 70 µM. The IC₅₀ values varied from 8.20 µM (in HCT116 (p53^-/-) colon cancer cells) to 35.10 µM (against HepG2 hepatocarcinoma cells) for 1, from 8.84 µM (in CEM/ADR5000 leukemia cells) to 48.99 µM (in MDA-MB-231 breast adenocarcinoma cells) for 2, from 12.17 µM (in CEM/ADR5000 cells) to 65.08 µM (in MDA-MB-231 cells) for 3, from 23.80 µM (in U87MG.ΔEGFR glioblastoma cells) to 68.66 µM (in HCT116 (p53^-/-) cells) for 4, from 4.84 µM (in HCT116 (p53^-/-) cells) to 13.12 µM (in HepG2 cells) for 5 and from 0.02 µM (against CCRF-CEM cells) to 122.96 µM (in CEM/ADR5000 cells) for doxorubicin. Compound 5 induced apoptosis in CCRF-CEM cells through alteration of MMP and increase in ROS production. In addition to apoptosis, ferroptosis was also identified as another mode of cell death induced by epunctanone.

CONCLUSIONS

Compounds 1-5 are valuable cytotoxic compounds that could be used to combat MDR cancer cells. Benzophenoe 5 is the most active molecule and deserve more investigations to develop new anticancer drugs.

New depsidone and dichromone from the stems of Garcinia paucinervis with antiproliferative activity

A new depsidone, paucinervin Q (1), a new dichromone, paucinervin R (2), and a known compound, paucinervin B (3), were isolated from the stems of Garcinia paucinervis by various chromatographic methods. Their structures were determined by analysis of spectroscopic data. The isolates were evaluated for their antiproliferative activity against three cancer cell lines HL-60, PC-3 and CaCo-2. Compound 1 showed significant inhibitory activities.