Cyclooxygenase Enzyme and Lipid Peroxidation Inhibitory Terpenoids and Steroidal compounds as Major Constituents in Cleome viscosa Leaves.

Bioassay guided study of Cleome viscosa Linn. (Cleomaceae) leaves led to the isolation of a new cembrenoid diterpene (1: ) and three known compounds (2:  - 4: ) from the hexane extract. The chemical structures of these compounds were elucidated by spectroscopic methods such as NMR (1D and 2D), HRMS and IR and identified and afforded compound 1: , malabaric acid (2: ), stigmast-4-en-3-one (3: ) and stigmast-4-ene-3,6-dione (4: ). This is the first report of compounds 1: and 2: from C. viscosa Linn. Isolates were evaluated for anti-inflammatory activity using in vitro cyclooxygenase enzyme (COX-1 and -2) inhibitory assays. The novel cembrenoid diterpene (1: ) exhibited IC50 values of 8.4 µM for COX-1 enzyme and 45.2 µM for COX-2 enzyme, respectively. Similarly, malabaric acid (2: ) exhibited IC50 values of 11.5 µM for COX-1 enzyme and 46.9 µM for COX-2 enzyme, respectively. Their inhibitory activities were in par with non-steroidal anti-inflammatory drugs aspirin, ibuprofen and naproxen. Sterols 3: and 4: gave IC50 values of 62.6 and 67.9 µM, respectively for COX-1 enzyme while indicating weak COX-2 enzyme inhibition. Lipid peroxidation inhibitory (LPO) and MTT assays were used to determine antioxidant activity of these compounds. Compounds 1:  - 4: showed LPO inhibition with IC50 values between 82 and 100 µM and moderate antioxidant activity in the MTT assay. Biological activities reported for these compounds are for the first time and it support anecdotal medicinal claims of C. viscosa Linn. leaves.

Pest-managing activities of plant extracts and anthraquinones from Cassia nigricans from Burkina Faso.

Insecticidal activity of eight plants collected from Burkina Faso was studied using mosquito (Ochlerotatus triseriatus), Helicoverpa zea and Heliothis virescens larvae and adult white fly (Bemisia tabaci). The n-hexane, ethyl acetate and methanol extracts of Pseudocedrela kotschyi, Strophantus hispidus, Securidaca longepedunculata, Sapium grahamii, Swartzia madagascariensis, Cassia nigricans, Jatropha curcas and Datura innoxia were used in this study. Extracts were tested at 250 microg/mL concentration. All three extracts of C. nigricans, J. curcas (skin and seeds) and D. innoxia exhibited 100% mortality on fourth instar mosquito (O. triseriatus) larvae. In addition, the n-hexane and ethyl acetate extracts of S. hispidus, S. longepedunculata, S. grahamii showed 100% mortality. The ethyl acetate extract of S. madagascariensis was the most active on adult white fly and exhibited 80% mortality. Extracts of all other plants exhibited 30-50% mortality on B. tabaci. In the antifeedant assays against H. zea and H. virescens, the MeOH extracts of C. nigricans, S. madagascarensis and S. hispidus were more effective against H. zea as indicated by 74% larval weight reduction as compared to the control. Since C. nigricans is commonly used in West Africa to protect grain storage from insects, we have characterized the insecticidal components present in its extract. Bioassay directed isolation of C. nigricans leaf extract yielded anthraquinones emodin, citreorosein, and emodic acid and a flavonoid, luteolin. Emodin, the most abundant and active anthraquinone in C. nigricans showed approximately 85% mortality on mosquito larvae Anopheles gambiaea and adult B. tabaci at 50 and 25 microg/mL, respectively, in 24 h. These results suggest that the extract of C. nigricans has the potential to be used as an organic approach to manage some of the agricultural pests.