Objective: To determine the potential antiulcer activity of methanol extract of Melastoma malabathricum leaves (MEMM) using various established rat models. Materials and Methods: Ten groups of rats were used and orally administered 10% DMSO (negative control), 100 mg/kg ranitidine (positive control) or MEMM (50, 250 and 500 mg/kg) followed by gastric ulcer induction either using ethanol or indomethacin. The stomachs were collected and subjected to macroscopic and microscopic analyses. Results: MEMM exhibited significant (p < 0.05) antiulcer activity in the ethanol, but not in the indomethacin-induced gastric ulcer model. The percentage of antiulcer activity for 50–500 mg/kg MEMM ranged between 3 and 75%, respectively. The gross observations were supported by histological findings. MEMM also aggravated the indomethacin-induced gastric ulcer, leading to an increase in ulcer area formation and ulcer score. Conclusion: The M. malabathricum leaves showed antiulcer activity, which could be attributed to their antioxidant and anti-inflammatory activities. This requires further in-depth studies.

The present study was carried out to elucidate the chemopreventive potential of methanol extract of Dicranopteris linearis (MEDL) in a two-stage mouse skin carcinogenesis model due to the interrelated inflammation, oxidative stress and tumor promotion pathways. MEDL was prepared in a dose range of 30 to 300 mg/kg body weight. A total of 48 imprinting control region (ICR) female mice (6 to 8 weeks old) were randomly assorted into six groups. To induce skin tumor formation, a single topical application of 7,12-dimethylbenz[a]anthracene (DMBA) at 100 μg/100 μl was applied to the shaved dorsal region of mice, followed by repetitive administration of 1% croton oil, twice weekly for 15 weeks. Topical application of MEDL, 30 min prior to the croton oil application significantly reduced the tumor incidence to 12.5% in 300 mg/kg MEDL-treated group as compared to 87.5% in carcinogen control. The latency period of tumor formation was increased from sixth week in the carcinogen control to ninth and fifteenth weeks in 100 and 300 mg/kg MEDL-treated groups, respectively. The tumor burden of MEDL-treated groups (30, 100, and 300 mg/kg) were significantly lessen (5.67 ± 1.28, 5.00 ± 1.13, and 1.00 ± 0.13), as compared to carcinogen control (7.86 ± 2.37). The tumor volume was also significantly reduced from 9.00 ± 2.27 mm 3 in carcinogen control to 3.70 ± 0.96, 2.39 ± 0.54 and 0.26 ± 0.03 mm 3 in 30, 100 and 300 mg/kg MEDL-treated groups, respectively. In conclusion, the MEDL exhibited anti-carcinogenic effect in a dose-dependent manner, indicating its chemopreventive potential, which worth further study.

Background: Melastoma malabathricum L. Smith (family Melastomaceae) is a shrub that has been used by the Malay practitioners of traditional medicine to treat various types of ailments. The present study aimed to determine the chemopreventive activity of methanol extract of M. malabathricum leaves (MEMM) using the standard 7,12-dimethylbenz(α)anthracene (DMBA)/croton oil-induced mouse skin carcinogenesis model. Materials and Methods:In the initiation phase, the mice received a single dose of 100µl/100 µg DMBA (group I-V) or 100µl acetone (group VI) topically on the dorsal shaved skin area followed by the promotion phase involving treatment with the respective test solutions (100 μl of acetone, 10 mg/kg curcumin or MEMM (30, 100 and 300mg/kg)) for 30 min followed by the topical application of tumour promoter (100µl croton oil). Tumors were examined weekly and the experiment lasted for 15 weeks. Results: MEMM and curcumin significantly (p<0.05) reduced the tumour burden, tumour incidence and tumour volume, which were further supported by the histopathological findings. Conclusion: MEMM demonstrated chemoprevention possibly via its antioxidant and anti-inflammatory activities, and the action of flavonoids like quercitrin.

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