Cowabenzophenones A and B, two new tetracyclo[7.3.3.33,11.03,7]tetradecane-2,12,14-trione derivatives, from ripe fruits of Garcinia cowa

Chemical Constituents and Biological Activities of Bruguiera Genus and Its Endophytes: A Review

The genus Bruguiera, a member of the Rhizophoraceae family, is predominantly found in coastal areas as a mangrove plant, boasting a rich and diverse community of endophytes. This review systematically compiled approximately 496 compounds derived from both the Bruguiera genus and its associated endophytes, including 152 terpenoids, 17 steroids, 16 sulfides, 44 alkaloids and peptides, 66 quinones, 68 polyketides, 19 flavonoids, 38 phenylpropanoids, 54 aromatic compounds, and 22 other compounds. Among these, 201 compounds exhibited a spectrum of activities, including cytotoxicity, antimicrobial, antioxidant, anti-inflammatory, antiviral, antidiabetic, insecticidal and mosquito repellent, and enzyme inhibitory properties, etc. These findings provided promising lead compounds for drug discovery. Certain similar or identical compounds were found to be simultaneously present in both Bruguiera plants and their endophytes, and the phenomenon of their interaction relationship was discussed.

Comprehensive studies of the anti-inflammatory effect of tetraprenyltoluquinone, a quinone from Garcinia cowa Roxb

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia cowa Roxb. is called asam kandis in West Sumatra. This plant contains several quinone compounds, including tetraprenyltoluquinone (TPTQ). The bioactivity of this compound has been tested as an anticancer agent. However, reports regarding its anti-inflammatory effects are still limited, especially against coronavirus disease (Covid-19).

AIM OF THE STUDY

This study explores the anti-inflammatory effect of TPTQ in silico, in vitro, and in vivo.

MATERIALS AND METHODS

In silico testing used the Gnina application, opened via Google Colab. The TPTQ structure was docked with the nuclear factor kappa B (NF-ĸB) protein (PDB: 2RAM). In vitro testing began with testing the cytotoxicity of TPTQ against Raw 264.7 cells, using the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) method. A phagocytic activity test was carried out using the neutral red uptake method, and interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) secretion tests were carried out using the enzyme-linked immunosorbent assay (ELISA) method. In vivo, tests were carried out on mice by determining cluster of differentiation 8+ (CD8+), natural killer cell (NK cell), and IL-6 parameters, using the ELISA method.

RESULTS

TPTQ has a lower binding energy than the native ligand and occupies the same active site as the native ligand. TPTQ decreased the phagocytosis index and secretion of IL-6 and TNF-α experimentally in vitro. TPTQ showed significant downregulation of CD8+ and slightly decreased NK cells and IL-6 secretion in vivo.

CONCLUSION

The potent inhibitory effect of TPTQ on the immune response suggests that TPTQ can be developed as an anti-inflammatory agent, especially in the treatment of Covid-19.

A review on natural products with cage-like structure

Natural products with diverse structures and significant biological activities are essential sources of drug lead compounds, and play an important role in the research and development of innovative drugs. Cage-like compounds have various structures and are widely distributed in nature, especially caged xanthones isolated from Garcinia genus, paeoniflorin and its derivatives isolated from Paeonia lactiflora Pall, tetrodotoxin (TTX) and its derivatives, and so on. In recent years, the development and utilization of cage-like compounds have been a research hotspot in chemistry, biology and other fields due to their special structures and remarkable biological activities. In this review, we mainly summarized the cage-like compounds with various structures found and isolated from natural drugs since 1956, summarized its broad biological activities, and introduced the progress in the biosynthesis of some compounds, so as to provide a reference for the discovery of more novel compounds, and the development and application of innovative drugs.

Polyisoprenylated benzophenone derivatives from Garcinia cambogia and their anti-inflammatory activities

Ten new polyisoprenylated benzophenone derivatives, 4,8-epi-uralione F (1), 4,8-epi-uralione G (2), uralione S (3), coccinone J (4), 6-epi-coccinone C (5), coccinone I (6), 36-hydroxy-guttiferone J (7), multiflorone I (8), garciniagifolone F (9) and 36-hydroxy-garciniagifolone F (10), were isolated from the fruits of Garcinia cambogia, along with seven known analogues. The structures of the new compounds were established based on the detailed analysis of 1D and 2D nuclear magnetic resonance (NMR) spectra and high resolution electrospray ionization mass spectrometra (HRESIMS), and their absolute configurations were determined from the electronic circular dichroism (ECD) spectra. All the isolates were tested for their inhibitory effects against nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The results indicated that compound 1 displayed a potent NO inhibitory effect with an IC50 value of 41.60 ± 0.17 μM. Furthermore, compound 1 suppressed inducible NO synthase (iNOS) expression in a dose-dependent manner through inhibiting the activation of nuclear factor-κB (NF-κB).

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.

Antimicrobial, anti-cancer, anti-filarial and anti-inflammatory activities of Cowabenzophenone A extracted from the endophytic fungus Aspergillus terreus isolated from a mangrove plant Bruguiera gymnorrhyza

Cowabenzophenone A was isolated from an endophytic fungus Aspergillus terreus isolated from a mangrove plant Bruguiera gymnorrhyza. The structure was determined by analysis of 1D and 2D NMR spectra and mass spectrometric data as a tetracyclo[7.3.3.33,11.03,7]tetradecane-2,12,14-trione skeleton. When the compound was tested in vitro for its ability to inhibit inflammations, α-glucosidase inhibitory activities and its antimicrobial properties, it showed an anti-inflammatory activity amounting to an IC50 of 12.1 µg/mL, α-glucosidase inhibitory activity, with IC50 values of 7.8 ± 0.5 μM, and antibacterial activity against Bacillus subtilis TISTR 088, and Bacillus cereus TISTR 688 with MIC values of 1 μg/mL and 2 μg/mL respectively. The compound showed cytotoxicity against HCT 116 colon cancer cell line with an IC50 value of 10.1 ?M, and also showed a considerably high potential towards anti-filarial activities by resulting MIC, IC50 and LC50 values of 0.358 ± 0.02 mg/mL, 0.708 ± 0.021 mg/mL and 3.89 ± 0.18 mg/mL, respectively, in comparison to the standard drug Ivermectin (IVM).

Research Progress of Polycyclic Polyprenylated Acylphloroglucinols

Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structure and bioactivity diversity. This review discusses the progress of research into the chemistry and biological activity of 421 natural PPAPs in the past 11 years as well as in-depth studies of biological activities and total synthesis of some PPAPs isolated before 2006. We created an online database of all PPAPs known to date at http://www.chem.uky.edu/research/grossman/PPAPs . Two subclasses of biosynthetically related metabolites, spirocyclic PPAPs with octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core and complicated PPAPs produced by intramolecular [4 + 2] cycloadditions of MPAPs, are brought into the PPAP family. Some PPAPs' relative or absolute configurations are reassigned or critically discussed, and the confusing trivial names in PPAPs investigations are clarified. Pharmacologic studies have revealed a new molecular mechanism whereby hyperforin and its derivatives regulate neurotransmitter levels by activating TRPC6 as well as the antitumor mechanism of garcinol and its analogues. The antineoplastic potential of some type B PPAPs such as oblongifolin C and guttiferone K has increased significantly. As a result of the recent appearances of innovative synthetic methods and strategies, the total syntheses of 22 natural PPAPs including hyperforin, garcinol, and plukenetione A have been accomplished.

Scalemic Caged Xanthones Isolated from the Stem Bark Extract of Garcinia propinqua

Seven new caged xanthones, doitunggarcinones E-K (1-7), all as scalemic mixtures and 10 known compounds (8-17), were isolated from the stem bark extract of Garcinia propinqua. The structures were elucidated on the basis of spectroscopic methods. The separation of the enantiomers of 1-6 was achieved by semipreparative chiral HPLC. The absolute configuration of compound (+)-1 was determined by single-crystal X-ray crystallographic analysis using Cu Kα radiation. The absolute configurations of the other related compounds were determined from comparisons of their ECD spectra with that of compound (+)-1. Compounds (-)-6 and 7 showed cytotoxicity against a colon cancer cell line with IC₅₀ values of 14.23 and 23.95 μM, respectively.

Polycyclic polyprenylated acylphloroglucinols: natural phosphodiesterase-4 inhibitors from Hypericum sampsonii

Seven novel PPAPs and 23 known analogs were isolated from Hypericum sampsonii, some of which were identified as potent PDE4 inhibitors.

Xanthones from Garcinia Propinqua Roots

Phytochemical investigation of Garcinia propinqua roots led to the isolation and identification of a new xanthone, doitunggarcinone D (1), together with 15 known compounds (2–16). Their structures were elucidated by intensive analysis of spectroscopic data. Compounds 3, 6, 7, 14, 15 and 16 exhibited strong antibacterial activity against Bacillus subtilis TISTR 088 with MIC values in the range of 1–4 μg/mL. Compounds 3, 7, 10 and 14 also showed good antibacterial activity against B. cereus TISTR 688 with MIC values ranging from 4–8 μg/mL.

Bioactive prenylated xanthones from the young fruits and flowers of Garcinia cowa

Five new xanthones, garciniacowones A-E (1-5), together with 14 known xanthones, 6-19, were isolated from the young fruits and fresh flowers of Garcinia cowa. The structures of 1-5 were elucidated by analysis of their 1D and 2D NMR spectra and mass spectrometric data. The compounds 1-19 were tested in vitro for their antimicrobial activity and for their ability to inhibit α-glucosidase. Compounds 16 and 17 showed the most potent α-glucosidase inhibitory activity, with IC50 values of 7.8 ± 0.5 and 8.7 ± 0.3 μM, respectively. Compounds 8, 9, and 19 showed antibacterial activity against Bacillus subtilis TISTR 088 with identical MIC values of 2 μg/mL, while 8, 10, and 19 exhibited antibacterial activity against Bacillus cereus TISTR 688 with identical MIC values of 4 μg/mL.

Antibacterial tetraoxygenated xanthones from the immature fruits of Garcinia cowa

A phytochemical investigation of the acetone extract from the immature fruits of Garcinia cowa led to the isolation of two novel tetraoxygenated xanthones, garcicowanones A (1) and B (2), together with eight known tetraoxygeanted xanthones. Their structures were determined by spectroscopic analysis. All isolated compounds were evaluated for their antibacterial activity against Bacillus cereus TISTR 688, Bacillus subtilis TISTR 008, Micrococcus luteus TISTR 884, Staphylococcus aureus TISTR 1466, Escherichia coli TISTR 780, Pseudomonas aeruginosa TISTR 781, Salmonella typhimurium TISTR 292 and Staphylococcus epidermidis ATCC 12228. α-Mangostin showed potent activity (MIC 0.25-1 μg/mL) against three Gram-positive strains and garcicowanone A and β-mangostin exhibited strong antibacterial activity against B. cereus with the same MIC values of 0.25 μg/mL.