Friedolanostanes and lanostanes from the leaves of Garcinia hombroniana

Phytochemical profile and diverse pharmacology of Garcinia celebica L

Garcinia celebica L. syn. Garcinia hombroniana Pierre belongs to the family Clusiaceae, is indigenous to Southeast Asian countries. This review aims to provide updated, comprehensive and categorized information on the phytoconstituents and pharmacological effects of this species. The data collection mainly involved searches through databases named Scopus, Google Scholar, Pubmed and Springer Link. Approximately 100 phytochemicals were recorded in this review, with various classes of compounds such as triterpenoids, flavonoids, benzophenones, xanthones, depsidones and sterols identified. The most abundant compounds isolated belong to two chemical classes: triterpenoids and xanthones. Their extracts and pure compounds have been reported for their antibacterial, antiparasitic, hepatoprotective, antioxidant, antidiabetic, antituberculosis, antiplatelet aggregation, anti-neuraminidase and cholinesterase inhibitory activities. This review will provide a comprehensive understanding between the phytochemical components and its medicinal uses that may serve as a valuable resource for future drug development.

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.

Cytotoxic lanostanes from fruits of Garcinia wallichii Choisy (Guttiferae)

Five new lanostanes, wallichinanes A-E (1-5) together with a known lanostane derivative 6 were isolated from the cytotoxic hexanes extract of fruits of Garcinia wallichii Choisy (Guttiferae). The structures of the isolated compounds were established by analysis of spectroscopic data, X-ray diffraction technique as well as comparison with the literature data. The cytotoxicity of all isolated compounds against a panel of cultured cancer cell lines was evaluated. Compound 4 exhibited good cytotoxicity with ED₅₀ values ranging from 3.91 to 7.63μM.

Apoptosis-mediated antiproliferative activity of friedolanostane triterpenoid isolated from the leaves of Garcinia celebica against MCF-7 human breast cancer cell lines

The leaves of Garcinia celebica strongly inhibit the proliferation of MCF-7 human breast adenocarcinoma cell lines. The present study focused on investigating the active anticancer and antiproliferative compound from the G. celebica leaves and assessing its mechanism of action. Ethanol extracts of G. celebica were fractionated based on their polarity using n-hexane, ethyl acetate and water. The antiproliferative properties were tested in vitro against MCF-7 human breast cancer cell lines using the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay. The active compound was subsequently isolated using column chromatography and identified by nuclear magnetic resonance. The characterized compound was also tested for its antiproliferative properties and the mechanism by which it induces apoptosis in MCF-7 cells by western blot analysis of the activated apoptotic proteins. This resulted in the isolation of a friedolanostane triterpenoid, which was determined to be methyl-3α, 23-dihydroxy-17,14-friedolanstan-8,14,24-trien-26-oat. This compound inhibited MCF-7 cell proliferation in a time- and dose-dependent manner with IC50 values of 82 and 70 µM for the 24 and 48 h treatments, respectively. Furthermore, the western blot analysis suggested that the compound exerted its anticancer activities by promoting apoptosis through the inhibition of the oncogenic protein Akt, thereby increasing the expression of poly (ADP-ribose) polymerase (PARP) protein. These results suggest that methyl-3α,23-dihydroxy-17,14-friedolanstan-8,14,24-trien-26-oat is the anticancer compound found in G. celebica, providing a basis for its potential use in cancer disease management.

Complete NMR assignments of bioactive rotameric (3 → 8) biflavonoids from the bark of Garcinia hombroniana

The genus Garcinia is reported to possess antimicrobial, anti-inflammatory, anticancer, hepatoprotective and anti-HIV activities. Garcinia hombroniana in Malaysia is used to treat itching and as a protective medicine after child birth. This study was aimed to isolate the chemical constituents from the bark of G. hombroniana and explore their possible pharmacological potential. Ethyl acetate extract afforded one new (1) and six (2-7) known 3 → 8 rotameric biflavonoids. Their structures were elucidated by UV, IR and NMR (1D and 2D) spectroscopy together with electron ionization/ESI mass spectrometric techniques and were identified as (2R, 3S) volkensiflavone-7-O-rhamnopyranoside (1), volkensiflavone (2), 4″-O-methyl-volkensiflavone (3), volkensiflavone-7-O-glucopyranoside (4), morelloflavone (5), 3″-O-methyl-morelloflavone (6) and morelloflavone-7-O-glucopyranoside (7). The absolute configuration of compound 1 was assigned by circular dichroism spectroscopy as 2R, 3S. The coexistence of conformers of isolated biflavonoids in solution at 25 °C in different solvents was confirmed by variable temperature NMR studies. At room temperature (25 °C), compounds 1-7 exhibited duplicate NMR signals, while at elevated temperature (90 °C), a single set of signals was obtained. Compound 5 showed significant in vitro antioxidant activities against 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis-3-ethyl benzthiazoline-6-sulfonic acid radicals. The antibacterial studies showed that compounds 5 and 6 are the most active against Staphylococcus aureus, Bacillus subtilis and Escherichia coli. Compounds 3 and 6 also showed moderate antituberculosis activity against H38 Rv. Based on the research findings, G. hombroniana could be concluded as a rich source of flavanone-flavone (3 → 8) biflavonoids that exhibit rotameric behaviour at room temperature and display significant antioxidant and antibacterial activities.

Cytotoxic benzophenone and triterpene from Garcinia hombroniana

Garcinia hombroniana (seashore mangosteen) in Malaysia is used to treat itching and as a protective medicine after child birth. This study was aimed to investigate the bioactive chemical constituents of the bark of G. hombroniana. Ethyl acetate and dichloromethane extracts of G. hombroniana yielded two new (1, 9) and thirteen known compounds which were characterized by the spectral techniques of NMR, UV, IR and EI/ESI-MS, and identified as; 2,3',4,5'-tetrahydroxy-6-methoxybenzophenone(1), 2,3',4,4'-tetrahydroxy-6-methoxybenzophenone (2), 2,3',4,6-tetrahydroxybenzophenone (3), 1,3,6,7-tetrahydroxyxanthone (4), 3,3',4',5,7-pentahydroxyflavone (5),3,3',5,5',7-pentahydroxyflavanone (6), 3,3',4',5,5',7-hexahydroxyflavone (7), 4',5,7-trihydroxyflavanone-7-rutinoside (8), 18(13→17)-abeo-3β-acetoxy-9α,13β-lanost-24E-en-26-oic acid (9), garcihombronane B (10), garcihombronane D (11), friedelan-3-one (12), lupeol (13), stigmasterol (14) and stigmasterol glucoside (15). In the in vitro cytotoxicity against MCF-7, DBTRG, U2OS and PC-3 cell lines, compounds 1 and 9 displayed good cytotoxic effects against DBTRG cancer cell lines. Compounds 1-8 were also found to possess significant antioxidant activities. Owing to these properties, this study can be further extended to explore more significant bioactive components of this plant.

Friedolanostanes and xanthones from the twigs of Garcinia hombroniana

The twigs of Garcinia hombroniana yielded six compounds: two 17,14-friedolanostanes (garcihombronanes K-L, 1-2) and four xanthones (garcihombronones A-D, 3-6) together with 14 known compounds including four friedolanostanes, one lanostane, six xanthones, two benzoic acid derivatives and one biflavonoid. Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously. Their antibacterial activity against methicillin-resistant Staphylococcus aureus and S. aureus was evaluated.

Cytotoxic triterpenoids from Abies recurvata

Nine triterpenoids (neoabiestrines A-I, 1-9) including six rearranged lanostanes (1-6) and a rare cycloart-7-ene (7) were isolated from Abies recurvata together with ten known compounds. Their structures were determined by detailed analysis of NMR and MS spectroscopic data. The absolute configurations of 1 and 8 were determined by Cu-Ka X-ray crystallography. Compound 6 showed potent anti-proliferative effect against THP-1 tumor cells with an IC(50) value of 17.8 μg/mL.

Triterpene Derivatives from Abies Spectabilis Leaves of Nepalese Origin

Our ongoing studies of Nepalese medicinal plants has led to the isolation and characterization of five new triterpenes, two known triterpenes and two phenolic derivatives from Abies spectabilis (D. Don) Mirb leaves grown in the high mountain. The structures of the isolated compounds were characterized by means of 1D and 2D NMR spectroscopic and MS techniques.

Flavanone glucuronides from the leaves of Garcinia prainiana

Phytochemical investigation of Garcinia prainiana ’s leaves led to the isolation of prainianonide (1), a new flavanone glucuronide, together with six known compounds: (2S)-eriodictyol 7-O-β-d-glucuronide (2), naringenin 7-O-β-d-glucuronide (3), (–)-GB-1a (4), (+)-morelloflavone (5), amenthoflavone (6), and friedelin (7). Their structures were elucidated by spectroscopic methods. The absolute configuration of 1 was determined by circular dichroism spectroscopy. Compounds 4 and 5 showed significant antioxidant activity.

Friedolanostane, friedocycloartane and benzophenone constituents of the bark and leaves of Garcinia benthami

Friedolanostanes, (22Z,24E)-3β-acetoxy-9α-hydroxy-17,14-friedolanosta-14,22,24-trien-26-oic acid, (22Z,24E)-3β,9α-dihydroxy-17,14-friedolanosta-14,22,24-trien-26-oic acid, (22Z,24E)-9α-hydroxy-3-oxo-17,14-friedolanosta-14,22,24-trien-26-oic acid, a friedocycloartane, (22Z,24E)-3α-hydroxy-17,13-friedocycloarta-12,22,24-trien-26-oic acid, and a benzophenone, benthaphenone, together with known compounds (22Z,24E)-3α,9α-dihydroxy-17,13-friedolanosta-12,22,24-trien-26-oic acid, methyl (24E)-3α,23-dihydroxy-17,14-friedolanosta-8,14,24-trien-26-oate, glutinol, lupeol, and stigmasterol, were isolated from leaves and bark of Garcinia benthami. Their structures were elucidated using spectroscopic techniques, mainly 1-D and 2-D NMR spectroscopy, and chemical correlations.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins. The literature from January 2005 to December 2006 is reviewed and 478 references are cited.