Phytochemical reactions and biological activities of a traditional thai herbal formula for asthma treatment: free radical scavenging and inhibition of lung cancer cell proliferation.

Lung cancer ranks as the third leading cause of cancer-related deaths in Thailand. Since there is currently no definitive cure, many researchers have turned to natural products in search of potential inhibitors of cancer cell proliferation. This study aimed at investigating the phytochemical reactions and biological activities of seven individual medicinal herbs (A-G) and a traditional Thai polyherbal formula (H). The herbs were extracted using ethanol (A1-H1) and water (A2-H2) as solvents. The resulting extracts were chemical reaction analyzed for the presence of 7 phytochemical groups. Free radical scavenging activity was evaluated using the DPPH assay. The inhibitory effect on lung cancer cell proliferation was assessed using the resazurin microplate assay. The H extracts contained all seven key phytochemical groups. However, both H1 and H2 demonstrated DPPH scavenging activity with SC50 values of 115.39 and 616.61 µg/ml, respectively. Only extracts D1, F1, and D2 had been able to inhibit the proliferation of small cell lung cancer with the Selectivity Index (SI) of 2.08, >1.29, and 7.11, respectively. Although the ethanol extract of the polyherbal formula had exhibited a relatively low level of bioactivity in this study, it also showed low cytotoxicity. Therefore, further investigations into its effects on other cancer cell lines or additional biological activities are recommended.