Dammrong Santiarworn

Antioxidant and anticancer activities from leaf extracts of four Combretum species from Northern Thailand

Four Combretum species (Combretaceae) from northern Thailand (Combretum deciduum, Combretum griffithii, Combretum latifolium and Combretum quadrangulare) were tested for antioxidant and anticancer activities. Antioxidant activities were assessed by ABTS and DPPH radical scavenging capacity methods. Anticancer activity was tested against three cancerous human cell lines (KB, MCF7 and NCI-H187). All methanolic leaf extracts showed antioxidant activities with the ABTS and DPPH methods. The methanolic leaf extracts of C. deciduum inhibited KB-oral cavity and MCF7-breast cancer cell lines, C. latifolium inhibited MCF7-breast cancer cell line and C. quadrangulare inhibited KB-oral cavity and NCI-H187-small cell lung cancer cell lines. However, the methanolic leaf extracts of C. griffithii were inactive against all three cell lines. All methanolic leaf extracts exhibited non-cytotoxicity to Vero cell lines.

The Chemical Constituents and the Cytotoxicity, Antioxidant and Antibacterial Activities of the Essential Oil of Graptophyllum pictum (L.) Griff.

Abstract The essential oil from the leaves of Graptophyllum pictum (L.) Griff. was isolated by hydrodistillation and its chemical constituents were investigated by a combination of gas chromatographic (GC-FID) and gas chromatography-mass spectrometric (GC-MS) analysis. Fourteen compounds, comprising 95.0 % of the gas chromatographical oil, were identified. The major constituents were phytol (75.7 %), n-nonacosane (6.5 %) and hexahydrofarnesyl acetone (2.6 %). The oil showed significant cytotoxicity against KB (epidermoid carcinoma of oral cavity), NCI-H187 (small cell lung carcinoma) and Vero cell lines with IC50 values of 27.04, 25.27 and 26.52 µg/mL, respectively. The antioxidant activity of the oil was determined using the ABTS radical cation scavenging assay. The oil had less antioxidant activity than the controls, trolox and ascorbic acid. In a disc diffusion assay the oil exhibited antibacterial activity against S. aureus and E. coli with MIC values of 11.75 and 35.25 µg/disc, respectively.