Abstract:

Objective ：To compare varieties and contents of vitamins of middle and upper leaves of Mentha haplocalyx Briq. (green- and purple-stem) and Mentha spicata L. resources. Method ：Water-soluble vitamins were determined by HPLC on Luna C18 (2) 100A (200 mm×4.6 mm, 5 μm) at 30 ℃ with 0.005 mol/L Hexane sodium-methanol (7:3, V/V) at pH 3.2 as mobile phase, detection wavelength 370 nm and flow rate 1.0 ml/ min. Fat-soluble vitamins were determined by HPLC on Hyperclone BDS C18 (150 mm×4.6 mm, 5μm) at 25 ℃ with methanol-ethyl acetate (95:5, V/V) as mobile phase, detection wavelength 275 nm and flow rate 1.0 ml/ min. Results: Only VC, VD2 and VK1 are found in younger leaves of M. haplocalyx Briq.and M. spicata L. The calibration curve of each vitamin is good. The average recoveries of VC, VD2 and VK1 are 99.85%, 81.61% and 90.27% respectively. The VC content of M. haplocalyx from Jianyang in Sichuan province is the highest, and the VD2 and VK1 contents of two M. haplocalyx cultivars from Chongqing are relatively high. The content of VC of M. spicata is commonly less than that of M. haplocalyx.The contents of VC of most purple-stem M. haplocalyx cultivars are higher than that in green- stem M. haplocalyx cultivars. There are no significant differences between the contents of VD2 and VK1 of M. haplocalyx and M. spicata, green- and purple-stem M. haplocalyx. Conclusion: HPLC method is suitable for simultaneous determination of vitamins in fresh leaves of Mentha L., M. haplocalyx and M. spicata cultivars have the same varieties of vitamins, while the contents of vitamins are different. There are some Mentha L. resources with higher vitamin contents. The content of VC of M. haplocalyx is commonly higher than that of M. spicata.

Key words: Mentha haplocalyx Briq., Mentha spicata L., vitamin, HPLC