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.

Phenolics and triterpenoids from stem bark of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens and their cytotoxic activities.

Genus Calophyllum is well-known for its phenolic constituents, especially coumarins, which have shown to have a wide range of significant biological activities. In this study, four known phenolic constituents and two triterpenoids have been isolated from the stem bark of Calophyllum lanigerum. The compounds were two pyranochromanone acids are known as caloteysmannic acid (1), isocalolongic acid (2), a simple dihydroxyxanthone, namely euxanthone (3), one coumarin named calanone (4), and two common triterpenoids, friedelin (5), and stigmasterol (6). Chromanone acids were reported for the first time in this Calophyllum species. Cytotoxic evaluations were carried out on n-hexane extract (87.14 ± 2.04 µg/mL; 81.46 ± 2.42 µg/mL) followed by the chromanone acids (1 [79.96 ± 2.39 µM; 83.41 ± 3.39 µM] & 2 [57.88 ± 2.34; 53.04 ± 3.18 µM]) against two cancerous cell lines, MDA-MB-231 and MG-63 cell lines, respectively. The results showed that all tested samples exhibited moderate cytotoxicity.

5,8-Dihy-droxy-2,2-dimethyl-12-(3-methyl-but-2-en-yl)pyrano[3,2-b]xanthen-6-one (brasixanthone B).

The title compound (trivial name brasixanthone B), C23H22O5, isolated from Calophyllum gracilentum, is characterized by a xanthone skeleton of three fused six-membered rings plus an additional fused pyrano ring and one 3-methyl-but-2-enyl side chain. The core xanthone moiety is almost planar, with a maximum deviation 0.057 (4) Šfrom the mean plane. In the mol-ecule, an intra-molecular O-H⋯O hydrogen bond forms an S(6) ring motif. The crystal structure features inter-molecular O-H⋯O and C-H⋯O inter-actions.

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, ß-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%.

Effects of Extraction Methods on Phenolic Content in the Young Bamboo Culm Extracts of Bambusa beecheyana Munro.

Nowadays, many studies focus on the potential of bamboo as a source of bioactive compounds and natural antioxidants for nutraceutical, pharmaceutical, and food sources. This study is a pioneering effort to determine the total phenolic content, total flavonoid content and free radical scavenging activity, as well as the phenolic identification and quantification of Bambusa beecheyana. The study was conducted by using ethanol, methanol, and water for solvent extraction by applying cold maceration, Soxhlet, and ultrasonic-assisted extraction techniques. The results showed that Soxhlet and ultrasonic-assisted Bambusa beecheyana culm extracts had an increase in the extract's dry yield (1.13-8.81%) but a constant p-coumaric acid (4) content (0.00035 mg/g) as compared to the extracts from the cold maceration. The ultrasonic-assisted extraction method required only a small amount (250 mL) of solvent to extract the bamboo culms. A significant amount of total phenolics (107.65 ± 0.01 mg GAE/g) and flavonoids (43.89 ± 0.05 mg QE/g) were found in the Soxhlet methanol culm extract. The extract also possessed the most potent antioxidant activity with an IC50 value of 40.43 µg/mL as compared to the positive control, ascorbic acid. The UHPLC-ESI-MS/MS analysis was carried out on the Soxhlet methanol extract, ultrasonic-assisted extract at 40 min, and cold methanol extract. The analysis resulted in the putative identification of a total of five phenolics containing cinnamic acid derivatives. The two cinnamic acid derivatives, p-coumaric acid (4) and 4-methoxycinnamic acid (5), were then used as markers to quantify the concentration of both compounds in all the extracts. Both compounds were not found in the water extracts. These results revealed that the extract from Soxhlet methanol of Bambusa beecheyana could be a potential botanical source of natural antioxidants. This study provides an important chemical composition database for further preclinical research on Bambusa beecheyana.

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.

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), ß-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, ß-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.

Cytotoxic activity of phytochemicals from Garcinia mangostana L. and G. benthamiana (Planch. & Triana) Pipoly against breast cancer cells.

Four xanthones, α-mangostin (1), ß-mangostin (2), mangostenol (3), mangaxanthone B (4), three benzophenones, mangaphenone (5), benthamianone (6), congestiflorone (7) and one sterol, stigmasterol (8) were isolated from the stem barks of Garcinia mangostana L. and G. benthamiana (Planch. & Triana) Pipoly. Compounds 1, 2, 4 and 5 exhibited significant cytotoxicity through MTT assay towards MCF-7 and MDA-MB-231 cells with the IC50 values range from 4.4 to 12.0 µM. Remarkably, mangaphenone (5) showed non-cytotoxicity against normal Vero cells, revealing its potential as lead compound for anti-breast cancer drug. Structure-activity relationship postulated that the prenyl and hydroxyl groups present in xanthones are important in promoting anti-proliferative effects. Molecular docking simulation study of 1, 2, 4 and 5 with 2OCF and 4PIV implied that the induction of apoptosis for both cancer cells involve ER and FAS signaling pathways. Future study on the lead optimization of 5 is highly recommended.

A new coumarin from stem bark of Calophyllum wallichianum.

A phytochemical study carried out on the plant, Calophyllum wallichianum has led to the isolation of a new coumarin, wallimarin T (1) and a known coumarin, calanolide E (2) along with two common triterpenes, friedelin (3) and stigmasterol (4). The structures of these compounds were elucidated with the aid of spectroscopic analyses such as FT-IR, GC-MS, and NMR. MIC assay against the Bacillus bacteria were conducted on the extracts and this gave MIC values ranging from 0.313 to 1.25 mg/mL. Compound 2 was weakly inhibitory towards the Bacilli strains with MIC values ranging from 0.25-0.50 mg/mL. Wallimarin T (1) was not active towards all four bacteria. Overall, the extracts exhibited weak bactericidal properties whereas compound 2 was not bactericidal on the tested bacteria. The hexane and chloroform extracts of the plant were found to be inhibitors to the growth of Bacillus megaterium, Bacillus cereus, Bacillus pumilus and Bacillus subtilis.

A new pyranoxanthone from Garcinia nervosa.

Phytochemical studies on the stem bark of Garcinia nervosa has resulted in the discovery of one new pyranoxanthone derivative, garner xanthone (1) and five other compounds, 1,5-dihydroxyxanthone (2), 6-deoxyisojacareubin (3), 12b-hydroxy-des-D-garcigerrin A (4) stigmasterol (5), and ß-sitosterol (6). The structures of these compounds were elucidated with the aid of spectroscopic techniques, such as NMR and MS. The crude extracts of the plant were assessed for their antimicrobial activity.

A new coumarin from stem bark of Mesua hexapetala.

A new alkylated coumarin derivative, hexapetarin (1) along with three other xanthones, trapezifolixanthone (2), cudraxanthone G (3) and 1,3,7-trihydroxy-2,4-di (3-methyl-2-butenyl)xanthone (4), and four common triterpenoids, friedelin (5), stigmasterol (6), beta-sitosterol (7) and gamma-sitosterol (8) were isolated from the stem bark of Mesua hexapetala (Clusiaceae), a plant, native to Malaysia. The structures of these compounds were elucidated and determined using spectroscopic techniques such as NMR and MS. Anti-inflammatory activity assay indicated hexapetarin (1) to possess moderate anti-inflammatory activity, while 1,3,7-trihydroxy-2,4-di (3-methyl-2-butenyl)xanthone (4) gave very good activity.

A new chromanone acid from the stem bark of Calophyllum teysmannii.

A new chromanone acid, namely caloteysmannic acid (1), along with three known compounds, calolongic acid (2), isocalolongic acid (3) and stigmasterol (4) were isolated from the stem bark of Calophyllum teysmannii. All these compounds were evaluated for their cytotoxic and antioxidant activities in the MTT and DPPH assays, respectively. The structure of compound 1 was determined by means of spectroscopic methods including 1D and 2D NMR experiments as well as HR-EIMS spectrometry. The stereochemical assignment of compound 1 was done based on the NMR results and X-ray crystallographic analysis. The preliminary assay results revealed that all the test compounds displayed potent inhibitory activity against HeLa cancer cell line, in particular with compound 1 which exhibited the highest cytotoxic activity comparable to the positive control used, cisplatin. However, no significant antioxidant activity was observed for all the test compounds in the DPPH radical scavenging capacity assay.

The pyranoxanthone inophyllin A induces oxidative stress mediated-apoptosis in Jurkat T lymphoblastic leukemia cells.

Inophyllin A (INO-A), a pyranoxanthone isolated from the roots of Calophyllum inophyllum represents a new xanthone with potential chemotherapeutic activity. In this study, the molecular mechanism of INO-A-induced cell death was investigated in Jurkat T lymphoblastic leukemia cells. Assessment of phosphatidylserine exposure confirmed apoptosis as the primary mode of cell death in INO-A-treated Jurkat cells. INO-A treatment for only 30 min resulted in a significant increase of tail moment which suggests that DNA damage is an early apoptotic signal. Further flow cytometric assessment of the superoxide anion level confirmed that INO-A induced DNA damage was mediated with a concomitant generation of reactive oxygen species (ROS). Investigation on the thiols revealed an early decrease of free thiols in 30 min after 50 µM INO-A treatment. Using tetramethylrhodamine ethyl ester, a potentiometric dye, the loss of mitochondrial membrane potential (MPP) was observed in INO-A-treated cells as early as 30 min. The INO-A-induced apoptosis progressed with the simultaneous activation of caspases-2 and -9 which then led to the processing of caspase-3. Taken together, these data demonstrate that INO-A induced early oxidative stress, DNA damage and loss of MMP which subsequently led to the activation of an intrinsic pathway of apoptosis in Jurkat cells.