New ent-kaurene and germacrene derivatives from Mesona procumbens Hemseley and their biological activity

Mesona procumbens Hemseley is a well-known traditional herbal medicine used for heat-related ailments. In Taiwan, boiled extracts of M. procumbens are also used as desserts called grass jelly. In this study, the hexane extract from 75% EtOH of M. procumbens showed potent activities on inhibition of E. coli β-glucuronidase (eβG) and NO production and cytotoxicity against MCF-7 and HepG2 cancer cell lines. Furthermore, using various flash columns and HPLC chromatography on the bioactive layer led to the isolation of twelve compounds (1-12), including a new ent-kaurene, mesokaurol A (1), and a new germacrene derivative, mesogermapene A (2). Their structures were elucidated by extensive spectroscopic analyses, especially 2 D NMR and mass data. Biological assays showed that compound 9 (linolenic acid) had specific activity on inhibition of eβG (68.27%) at 100 µg/mL but was non-inhibitory to human β-glucuronidase. Compound 1 possessed significant cytotoxicity against MCF-7 (EC₅₀ = 9.76 µM) and HepG2 (EC₅₀ = 8.64 µM) cancer cell lines.

Separation and anti-inflammatory evaluation of phytochemical constituents from Pleurospermum candollei (Apiaceae) by high-speed countercurrent chromatography with continuous sample load

Pleurospermum (Apiaceae) species possess a wide range of biological properties viz. analgesic, anti-inflammatory, antimalarial, and so on. Pleurospermum candollei (DC.) Benth. Ex C. B. Clark. is reported to cure diarrhea, gastric, respiratory, stomach, abdominal, joint, and back pain problems. In addition, it is also used for both male and female infertility. The present study deals with an efficient technique using high-speed countercurrent chromatography for separation of chemical components from the methanol extract of P. candollei. Notably, nine main compounds namely luteolin 7-O-glucoside (1), oxypeucedanin hydrate (2), pabulenol (3), bergapten (4), heptadecanoic acid (5), (E)-isoelemicin (6), trans-asarone (7), α-linolenic acid (8), and isoimperatorin (9) were very efficiently separated and isolated in pure form. Multiple injections were applied followed by two off-line recycling high-speed countercurrent chromatography. The inhibitory effect of nitric oxide production of all compounds was tested in the presence of 200 ng/mL lipopolysaccharide in RAW264.7 mice macrophage cells. The results demonstrated that compounds 7 and 8 effectively inhibited nitric oxide production, with IC₅₀ values of 28.44 and 53.18 μM, respectively. This study thus validates the traditional claim of using P. candollei. Taken together, these findings will be useful in future research to find a potential candidate with anti-inflammatory properties.