Isolation and structural modifications of ananixanthone from Calophyllum teysmannii and their cytotoxic activities

Isolation, derivatization, and anti-microbial evaluation of secondary metabolites from Garcinia dryobalanoides

A detailed study on secondary metabolites from the stem bark of Garcinia dryobalanoides has yielded one triterpenoid and four xanthones. Along with that, five novel rubraxanthone derivatives had been successfully synthesised via Williamson etherification with various alkyl halides. The antibacterial evaluation on crude extract, isolated secondary metabolites (1-5), and synthesised compounds (6-9) against Lactiplantibacillus plantarum, Enterobacter cloacae, Pseudomonas aeruginosa, and Serratia marcescens demonstrated moderate to active activities outlining their bacteriostatic potential. The structure-activity relationship (SAR) study conducted revealed the presence of prenyl and hydroxy groups on the xanthone attributed to good bacterial inhibition. The introduction of the alkyl chain to the hydroxy part eventually decreases the antibacterial activity of the compound which is probably due to the bulkiness that causes steric hindrances, therefore limiting the ability to bind to its target site within the bacterial cell.

Chemical constituents from the stem barks of Calophyllum recurvatum P.F. Stevens and Calophyllum andersonii P.F. Stevens, and their in-vitro hepatotoxic activity

Bioactive phenolics can be found in abundance in Calophyllum species. Phytochemical studies are carried out on the stem bark of Calophyllum recurvatum and Calophyllum andersonii, which has led to the isolation and elucidation of phytochemicals, thwaitesixanthone (1), teysmanone A (2), soulattrolide (3), calanone (4), isocalanone (5) and friedelin (6), respectively. The cytotoxic activities of compounds (2), (3), (4) and (5) as well as plant extracts were tested against HeLa Chang liver, HepG2 and HL-7702 cell lines. Phenylpyranocoumarins, teysmanone A (2) and soulattrolide (3) portrayed appreciable cytotoxicity activities at 42.57 ± 1.20 and 34.53 ± 3.41 µg/mL, respectively against HepG2 cell line comparable to the positive control, curcumin. Meanwhile, n-hexane extract from C. recurvatum exhibited cytotoxicity with the IC50 value of 36.43 ± 0.64 and 26.25 ± 4.83 µg/mL against HeLa Chang liver and HepG2 cell lines. All the tested compounds and plant extracts displayed non-cytotoxic properties on HL-7702 cell line.

A Review of the Ethnomedicinal, Phytochemical, and Anticancer Properties of Melicope Species

The genus Melicope, which consists of 230 species, stands out as the largest genus within the Rutaceae family. Melicope species are characterized by their evergreen nature and can range from shrubs to predominantly dioecious trees. The Melicope species have been utilized in traditional medicine to address a wide range of ailments, including fever, colds, cramps, and inflammation. These plants have gained significant attention due to their noteworthy ethnopharmacological and ethnomedicinal significance. Researchers have isolated numerous biologically active secondary metabolites from different Melicope species, which include polymethoxylated flavonoids, furanocoumarins, acetophenones, benzenoids, and quinolone alkaloids. These compounds exhibit diverse biological activities, such as antibacterial, antidiabetic, antifungal, and antiproliferative properties against human cancer cell lines. This review provides an update on the chemical constituents of the selected species of Melicope. The study also highlights the anticancer and cytotoxicity properties of the plant extracts and phytochemical constituents from Melicope species. Furthermore, the molecular mechanisms underlying the anticancer effects are elucidated. Overall, this review contributes to understanding the significant pharmacological potential of Melicope species and unlocking their chemical composition, emphasizing their relevance in the development of therapeutic agents, particularly in the field of cancer research.

Garcinia oligantha: A comprehensive overview of ethnomedicine, phytochemistry and pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Garcinia oligantha Merr. is an ethnomedicine plant mainly distributed in Guangdong and Hainan, China. It has the effects of heat-clearing and detoxicating, which has been used by local ethnic minorities to treat a variety of diseases, including inflammation, internal heat, toothache and scald.

THE AIM OF THE REVIEW

This review summarizes and discusses the progress of the chemical compounds and biological activities of G. oligantha that have been studied in recent years to provide the direction for the prospective research and applications of G. oligantha.

MATERIALS AND METHODS

The relevant literature about G. oligantha was accessible from ancient Chinese medical books and records, theses, as well as major scientific databases such as Google Scholar, PubMed, Web of Science, ScienceDirect, SciFinder, Baidu Scholar and China National Knowledge Infrastructure (CNKI).

RESULTS

To date, more than 150 chemical compounds were isolated from this plant, including xanthones, volatile oil, fatty acid, benzofurane derivative and biphenyl compounds. Xanthones are the main bioactive compounds that exhibit diverse biological effects, such as antitumor, analgesic, anti-inflammatory, antioxidative, neuroprotective, antimalarial and antibacterial effects, which are consistent with its traditional uses as a folk medicine. Modern pharmacological studies show that these compounds participate in a variety of signaling pathways underlying different pathophysiologies, making them a valuable medicinal resource.

CONCLUSION

G. oligantha is an ethnomedicine with a long history. However, due to regional and cultural constraints, the popularisation and use of ethnomedicine are still limited. Modern pharmacological and chemical research suggest that G. oligantha contains a variety of bioactive compounds and showed diverse biological functions, which is worthy of comprehensive and in-depth research. This review summarizes and discusses the recent progress in studies on G. oligantha, looking forward to promote further research and sustainable development of folk medicinal plants.

Phytochemicals from Calophyllum canum Hook f. ex T. Anderson and their neuroprotective effects

Previous phytochemical investigations reported that Calophyllum spp have biosynthesized a wide range of bioactive phenolics such as xanthones and coumarins. The phytochemical study conducted on the stem bark of C. canum has led to the isolation of eight trioxygenated xanthones namely: 5-methoxytrapezifolixanthone (1), 5-methoxyananixanthone (2), caloxanthone C (3), 1,5-dihydroxy-3-methoxy-4-isoprenylxanthone (4), 6-deoxyisojacareubin (5), euxanthone (6), trapezifolixanthone (7), ananixanthone (8), together with three common triterpenoids, β-sitosterol (9), friedelin (10), and stigmasterol (11). Furthermore, xanthones 1 and 2 were isolated for the first time as naturally occurring xanthones from the plant extract. The structures of these compounds were identified and elucidated using advanced spectroscopic techniques such as 1 D & 2 D NMR, MS, and FTIR. The neuroprotective property of selected compounds was tested through in vitro stroke model. Among all tested compounds, 1 µm of compounds 8, 9, and 10 showed significant neuroprotective activity via reduction of apoptosis by ∼ 50%.

Two New Xanthones from the Twigs of Calophyllum membranaceum and Their Anti-Inflammatory Activities in HESC Cells

Two new xanthones, calmemxanthone A (1) and calmemxanthone B (2), along with eleven known compounds were isolated from the dried twigs of Calophyllum membranaceum Gardn. et Champ. The structures of compounds 1 and 2 were established by analysis of spectra and mass spectrometry data. The absolute configuration of compound 1 was confirmed by electronic circular dichroism (ECD) spectral analysis. The anti-inflammation action of these compounds were evaluated on lipopolysaccharide (LPS)-induced inflammatory damage to human endometrial stromal cells (HESCs), and the structure-activities of 1-13 were also discussed. Compound 10 presented the anti-inflammation action with an IC₅₀ value of 20.3 μM, that might be relevant to the regulation of NF-κB signaling pathway via the suppression of TRIF, IKKα, and IκBα.

An Update on the Anticancer Activity of Xanthone Derivatives: A Review

The annual number of cancer deaths continues increasing every day; thus, it is urgent to search for and find active, selective, and efficient anticancer drugs as soon as possible. Among the available anticancer drugs, almost all of them contain heterocyclic moiety in their chemical structure. Xanthone is a heterocyclic compound with a dibenzo-γ-pyrone framework and well-known to have "privileged structures" for anticancer activities against several cancer cell lines. The wide anticancer activity of xanthones is produced by caspase activation, RNA binding, DNA cross-linking, as well as P-gp, kinase, aromatase, and topoisomerase inhibition. This anticancer activity depends on the type, number, and position of the attached functional groups in the xanthone skeleton. This review discusses the recent advances in the anticancer activity of xanthone derivatives, both from natural products isolation and synthesis methods, as the anticancer agent through in vitro, in vivo, and clinical assays.

A new xanthone dimer and cytotoxicity from the stem bark of Calophyllum canum

A phytochemical investigation of the stem bark of Calophyllum canum resulted in the isolation of a new xanthone dimer identified as biscaloxanthone (1), together with four compounds; trapezifoliaxanthone (2), trapezifolixanthone A (3), taraxerone (4) and taraxerol (5). The structures of these compounds were determined via spectroscopic methods of IR, UV, MS and NMR (1D and 2D). The cytotoxicity of compounds 1-3 were screened against A549, MCF-7, C33A and 3T3L1 cell lines, wherein weak cytotoxic activities were observed (IC₅₀ > 50 μm).

Cytotoxicity and nitric oxide inhibitory activities of Xanthones isolated from Calophyllum hosei Ridl

Previous studies on Calophyllum species have shown the existence of a wide variety of bioactive xanthones and coumarins. Phytochemical investigations carried out on the plant, Calophyllum hosei led to the isolation of eleven known xanthones, ananixanthone (1), 9-hydroxycalabaxanthone (2), dombakinaxanthone (3), thwaitesixanthone (4), caloxanthone B (5), trapezifolixanthone (6), β-mangostin (7), osajaxanthone (8), caloxanthone A (9), calozeyloxanthone (10) and rubraxanthone (11). The structures of these compounds were identified and elucidated using spectroscopic techniques such as NMR and MS. The cytotoxicity and nitric oxide production inhibitory activities of selected xanthones as well as the extracts were tested against HL-60 cells and RAW 264.7 murine macrophages, respectively. Among all tested compounds, β-mangostin exhibited appreciable cytotoxicity against HL-60 cells with the IC₅₀ value of 7.16 ± 0.70 µg/mL and rubraxanthone exhibited significant nitric oxide inhibitory activity against LPS induced RAW 264.7 murine macrophages with the IC₅₀ value of 6.45 ± 0.15 µg/mL.

Phytochemicals from Calophyllum macrocarpum Hook.f. and its cytotoxic activities

Species from the Genus Calophyllum are rich source for bioactive phenolic compounds such as coumarins and xanthones. Phytochemical study carried out on the plant, Calophyllum macrocarpum has led to the isolation of three known prenylated xanthones, ananixanthone (1), trapezifolixanthone (2) and 8-deoxygartanin (3) with two common triterpenoids, stigmasterol (4), and friedelin (5). The structures of these compounds were identified and determined using spectroscopic techniques such as NMR and MS. The cytotoxic activities of compounds 1 and 2 as well as the extracts were tested against HeLa Chang liver and HEK-293 cell lines. Compound 1 exhibited appreciable cytotoxicity with the IC₅₀ value of 11.08 ± 3.09 µM against HeLa Chang liver cell line and moderate cytotoxicity against HEK-293 cell line while compound 2 showed limited toxicity against these two cell lines.