Chemical constituents and their biological activities of Ludisia discolor

In order to explore the chemical constituents and their biological activities of Ludisia discolor, gas chromatography-mass spectrometry(GC-MS)was carried out to analyze the chemical constituents of petroleum ether fraction of ethanol extracts. Meanwhile, the compounds were isolated from the ethyl acetate fraction by using various column chromatography including silica gel, Sephadex LH-20, and semi-preparative HPLC. MS and nuclear mgnetic resonance(NMR)spectroscopic analysis were used to identify the structure of the compounds. And then the isolated compounds were tested for anti-inflammatory with RAW 264.7 cells, and antioxidant activities were carried out with DPPH and ABTS·+ free radical scavenging ability. The results showed as follows:(1)A total of 17 compounds were identified from the petroleum ether fraction of L. discolor, in which, methyl palmitate, methyl linoleate, methyl linolenic acid, and 2-monopalmitin had a relatively high content.(2)A total of 15 compounds were isolated from the ethyl acetate fraction, their structures were identified as matairesinol(1),(+)-pinoresinol(2), callyspongidipeptide A(3), cyclo- [(S)-Pro-(R)-Leu](4), epi-boscialin(5), dibutyl terephthalate(6), methyl 4-hydroxycinnamate(7), 1-(4-hydroxyphenyl)ethanone(8), 4-hydroxybenzyl alcohol(9), p-hydroxy-benzaldehyde(10), vanillin(11), 4-(methoxym-ethyl)phenol(12), β-sitosterol(13), tetradecanoic acid(14), and palmitic acid(15), respectively. Compounds 1-15 were isolated from L. discolor for the first time.(3)Phenylpropanoid compounds 1 and 2 showed moderate inhibition on NO production from RAW264.7 cells induced by LPS, with IC50 values of(37.76 ± 2.68)μmol·L-1 and(53.14 ± 1.63)μmol·L-1 [(quercetin as the positive control, with IC50 value of(9.32 ± 0.36)μmol·L-1], respectively. Antioxidant results showed that compounds 1 and 2 had moderate DPPH free radical scavenging ability, with IC50 values of(51.22 ± 1.07)μg·mL-1 and(79.22 ± 7.44)μg·mL-1 [vitamin C as the positive control, with IC50 value of(6.01±0.17)μg·mL-1], respectively. Meanwhile, they had stronger ABTS·+ free radical scavenging ability than the positive control trolox [IC50 =(34.65 ± 0.53)μg·mL-1], with IC50 values of(2.21 ± 0.01)μg·mL-1 and(3.58 ± 0.17)μg·mL-1, respectively. Overall, this study enriched the chemical constituents of L. discolor, and it was further clarified that phenolic compounds are the active antioxidant constituents in L. Discolor, and phenylpropanoid compounds have certain anti-inflammatory activities, which provides a chemical structure basis for subsequent in-depth pharmacological research.