Isolation of Sesquiterpene-Amino Acid Conjugates, Onopornoids A-D, and a Flavonoid Glucoside from Onopordum alexandrinum.

Previous phytochemical investigations have revealed the presence of a variety of compounds such as pyrrolidine derivatives, flavonoids, and megastigmanes in Egyptian plants. Onopordum alexandrinum has been traditionally used by the natives for treatment of skin cancers and leprosy. In this paper the isolation of four new sesquiterpene-amino acid conjugates, onopornoids A-D (1-4), i.e., three elemanes and one germacrane, and a new acylated flavonoid glucoside (5) along with nine known compounds (6-14) from the whole aerial parts of the title plant is discussed. The structures were elucidated based on chemical and spectroscopic/spectrometric data.

Anti-inflammatory sesquiterpenes from Costus speciosus rhizomes.

ETHNOPHARMACOLOGICAL RELEVANCE: Costus speciosus (Koen ex. Retz.) Sm. (crepe ginger, family Costaceae) is an ornamental plant used in traditional medicine for the treatment of inflammation, rheumatism, bronchitis, fever, headache, asthma, flatulence, constipation, helminthiasis, leprosy, skin diseases, hiccough, anemia, as well as burning sensation on urination. AIM OF THE STUDY: The present study is designed to isolate and identify the active compounds from C. speciosus rhizomes and measure their anti-inflammatory activities. MATERIALS AND METHODS: The n-hexane-CHCl3 soluble fraction of the MeOH extract of C. speciosus rhizomes has been subjected to a repeated column chromatography, including normal silica gel and RP-18 column to give eight compounds. The structures of these compounds were established by UV, IR, 1D ((1)H and (13)C), and 2D ((1)H-(1)H COSY, NOESY, HSQC, and HMBC) NMR experiments and HRESIMS data. In addition, the anti-inflammatory activity of compounds 1-8 was evaluated by measuring the levels IL-6, IL-1ß, TNF-α, COX-2, lipoxgenase-5, and PGE2 using enzyme-linked immunosorbent assay. RESULTS: The n-hexane-CHCl3 soluble fraction afforded a new eudesmane acid, specioic acid (8), along with seven known compounds, 22,23-dihydrospinasterone (1), dehydrodihydrocostus lactone (mokko lactone) (2), dehydrocostus lactone (3), stigmasterol (4), arbusculin A (5), santamarine (douglanin) (6), and reynosin (7). Compounds 1, 4, and 5-7 were isolated for the first time C. speciosus. Compounds 1-4 displayed potent anti-inflammatory activity, while 7 and 8 showed moderate activity. Compounds 1-8 exhibited a concentration-related decrease in the levels of IL-1ß, IL-6, TNF-α, PGE2, lipoxgenase-5, and COX-2. Compounds 5 and 6 did not significantly decrease levels of different cytokines, PGE2, lipoxgenase-5, and COX-2 from PHA treatment at 1 µM. However, all tested compounds significantly decreased cytokines, PGE2, lipoxgenase-5, and COX-2 levels at concentration 100 µM. It is noteworthy that compounds 1-4 had the highest activity, where it lowered levels of cytokines, PGE2, lipoxgenase-5, and COX-2 to the extent that was no statistical difference from the control group. Thus, they decreased proinflammatory cytokines (IL-1ß, IL-6, and TNF-α) with decreased level of the target enzymes (COX-2 and lipoxgenase-5) and subsequent reduction of its inflammatory product (PGE2). CONCLUSION: Good anti-inflammatory activities exhibited of the isolated compounds from C. speciosus corroborate the usefulness of this plant in the traditional treatment of inflammation and related symptoms.