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).

A lignan with glucose uptake activity in 3T3-L1 adipocytes from the stem bark of Knema patentinervia.

A new naturally occurring dibenzylbutyrolactone lignan named isocubebinic ether has been isolated from Knema patentinervia. The structure was established by spectroscopic methods, which include Ultraviolet, Infrared, Nuclear Magnetic Resonance and Mass Spectrometry. The compound showed activity in the stimulation of glucose uptake by 3T3-L1 adipocytes.

Cytotoxic tirucallane triterpenes from the stem of Luvunga scandens

Two tirucallane triterpenes, namely flindissol (1) and 3-oxotirucalla-7,24-dien-21-oic-acid (2), were isolated from the dichloromethane extract of the stem of Luvunga scandens (Roxb.) Buch-Ham ex Wight & Arn, Rutaceae. This is the first report of their isolation from this plant. Their structures were constructed by high resolution mass and 2D NMR spectroscopic data. The cytotoxic potential of the two pure compounds 1 and 2 were determined by MTT assay against human breast adenocarcinoma cell line (MCF-7). Compounds 1 and 2 showed potent cytotoxicity against MCF-7 cell line with IC50 values of 13.8 μM and 27.5 μM, respectively. This result suggested their potential activity as antitumor agents.

Haplophytin B from Maclurodendron porteri.

An alkaloid from Maclurodendron porteri has been isolated and characterized. Extraction process was conducted by acid-base extraction method followed by column chromatography. The structure was established by nuclear magnetic resonance spectroscopy and mass spectrometry. The compound was identified as haplophytin B which occurs commonly in the Rutaceae family. However, this is the first time this alkaloid was isolated and reported from the species. The compound showed no inhibition against Staphylococus aureus, Pseudomonas aeruginosa, Bacillus cereus and Escherichia coli and no cytotoxic activity against H199 and A549 cell lines.

Friedelin and lanosterol from Garcinia prainiana stimulated glucose uptake and adipocytes differentiation in 3T3-L1 adipocytes.

Friedelin and lanosterol have been isolated from twigs of Garcinia prainiana. Their structures were elucidated by spectroscopic methods. The compounds were examined for their effects on 3T3-L1 adipocytes. In the MTT assay, it was found that the compounds had no cytotoxic effects up to 25 µM. Adipocyte differentiation analysis was carried out by Oil Red O staining method. In the presence of adipogenic cocktail (MDI), it was found that friedelin and lanosterol enhanced intracellular fat accumulation by 2.02 and 2.18-fold, respectively, compared with the vehicle-treated cells. Deoxyglucose uptake assay was used to examine the insulin sensitivity of adipocytes in the presence of the compounds. It was found that friedelin was able to stimulate glucose uptake up to 1.8-fold compared with insulin-treated cells. It was suggested that friedelin and lanosterol may be beneficial to mimic insulin action that would be useful in the treatment of diabetes type 2 patients.

Apoptosis, antimicrobial and antioxidant activities of phytochemicals from Garcinia malaccensis Hk.f.

OBJECTIVE: To study the chemical constituents of stembark of Garcinia malaccensis (G. malaccensis) together with apoptotic, antimicrobial and antioxidant activities. METHODS: Purification and structure elucidation were carried out by chromatographic and spectroscopic techniques, respectively. MTT and trypan blue exclusion methods were performed to study the cytotoxic activity. Antibacterial activity was conducted by disc diffusion and microdilution methods, whereas antioxidant activities were done by ferric thiocyanate method and DPPH radical scavenging. RESULTS: The phytochemical study led to the isolation of α,ß-mangostin and cycloart-24-en-3ß-ol. α-Mangostin exhibited cytotoxic activity against HSC-3 cells with an IC(50) of 0.33 µM. ß- and α-mangostin showed activity against K562 cells with IC(50) of 0.40 µM and 0.48 µM, respectively. α-Mangostin was active against Gram-positive bacteria, Staphylococcus aureus (S. aureus) and Bacillus anthracis (B. anthracis) with inhibition zone and MIC value of (19 mm; 0.025 mg/mL) and (20 mm; 0.013 mg/mL), respectively. In antioxidant assay, α-mangostin exhibited activity as an inhibitor of lipid peroxidation. CONCLUSIONS: G. malaccensis presence α- and ß-mangostin and cycloart-24-en-3ß-ol. ß-Mangostin was found very active against HSC-3 cells and K562. The results suggest that mangostins derivatives have the potential to inhibit the growth of cancer cells by inducing apoptosis. In addition, α-and ß-mangostin was found inhibit the growth of Gram-positive pathogenic bacteria and also showed the activity as an inhibitor of lipid peroxidation.