Comparative Research of Bioactivity and Analysis of Petroleum Ether Components in Flower and Tuber of Bletilla Striata

OBJECTIVE To analyze the petroleum ether components in flower and tuber of Bletilla striata and compare their biological activity. METHODS Petroleum ether (60-90℃) was used to the extraction solvent of soxhlet extraction method to extract petroleum ether components in flower and tuber of B. striata. The chemical compositions of petroleum ether components in flower and tuber of B. striata were analyzed by GC-MS, and they were also evaluated for antimicrobial activity by paper disc diffusion method, and antitumor activity by CCK8 method, while their antioxidant activity in vitro were evaluated by removal ability of DPPH and ABTS and OH free radicals. And their inhibitory effects on alpha amylase were determined by spectrophotometric method. RESULTS Twenty kinds of petroleum ether components were identified from flower and tuber of B. striata. Flower had 11 kinds of them, and tuber had 19 and there were 10 in common. 2-Acetylbutyrolactone (15.20%, 21.84%) and benzyl alcohol (12.07%, 24.10%) were in the majority. The bacteriostatic activity of petroleum ether components in flower was higher than the petroleum ether components in tuber, especially for Bacillus subtilis, the minimal inhibitory concentration and minimal bactericidal concentrations were 0.41, 0.51 g·L^-1 and 0.53, 0.66 g·L^-1 respectively. Inhibition rate of petroleum ether components in tuber on A549 cells was 29.451% and was higher than the petroleum ether components in flower which was 27.621%, when the mass concentration reached 5.0 mg·mL^-1. The IC₅₀ of the former on alpha amylase was 1.819 mg·mL^-1 and the latter was 2.028 mg·mL^-1. The scavenging rate of DPPH free radicals, ABTS free radicals and hydroxyl radical increased with the increase of mass concentration. When the mass concentration reached 1.0 mg·mL^-1, the scavenging rates of former on ABTS free radicals and hydroxyl free radical were 99.67% and 92.22% respectively, and were higher than the latter which were 90.07%, 38.11% respectively, while the scavenging rate of latter on DPPH free radicals was 31.23%, and was higher than the former which was 18.94%. But both of them in scavenging rates of DPPH free radicals, ABTS free radicals and hydroxyl radical were lower than Vc. CONCLUSION Lipids and alcohols are in the majority in petroleum ether components in flower and tuber of B. striata. Both of them have significant biological activity. Therefore they have potential medicinal value, and can provide reference for exploiting resources of B. striata.