Antiprotozoal, antimycobacterial, and anti-inflammatory evaluation of Cnidoscolus chayamansa (Mc Vaugh) extract and the isolated compounds

Cnidoscolus chayamansa is a medicinal and edible plant known as Chaya, is commonly used as an anti-inflammatory, antiprotozoal, antibacterial agent and as a remedy for respiratory illness, gastrointestinal disorders, and vaginal infections related with the inflammation process. In this paper, we describe the plant's phytochemical analysis and biological activities (antimycobacterial, antibacterial, antiprotozoal, and anti-inflammatory properties) of the CHCl₃:MeOH (1:1) leaves extract and isolated compounds, as well as the acute and sub-acute toxic effects. Chemical identification of isolated compounds was performed by ¹H- and ¹³C NMR spectra data. In vitro antibacterial and antimycobacterial activities were determined by disc diffusion and MABA assays, respectively; antiprotozoal test by means of the sub-culture test. Topical and systemic anti-inflammatory effects were tested by TPA and carrageenan assay on BALB/c mice. Moretenol, moretenyl acetate, kaempferol-3,7-dimethyl ether, and 5-hydroxy-7-3′,4′-trimethoxyflavanone were the main compounds isolated. The CHCl₃:MeOH extract showed antiprotozoal (IC₅₀ ≤65.29 μg/mL), antimycobacterial (MIC ≤50 μg/mL), and anti-inflammatory activities (ED₅₀ = 1.66 mg/ear and 467.73 mg/kg), but was inactive against the bacterial strains tested. The LD₅₀ for extract was >2g/kg. In the sub-acute toxicity test, the extract was administered at 1 g/kg for 28 days and did not cause lethality or any alteration in hematological and biochemical parameters; in addition, liver, kidney, and spleen histological analysis exhibited no structural changes. Moretenol and moretenyl acetate showed MIC = 25 μg/mL against Mycobacterium tuberculosis H37Rv and against four monoresistant strains of M. tuberculosis H37Rv. Both compounds exhibited moderate activity against Entamoeba histolytica and Giardia lamblia (IC₅₀ ≤ 71.70 μg/mL). Kaempferol-3,7-dimethyl ether and 5-hydroxy-7-3′,4′-trimethoxy-flavanone were more active than the extract against E. histolytica and G. lamblia, showing IC₅₀ ≤27.43 μg/mL. As topical anti-inflammatory agents, moretenol and kaempferol-3,7-dimethyl ether were the most active compounds inhibiting the edema in 30.52 and 26.67%, respectively. Moretenol and moretenyl acetate showed significant antimycobacterial and antiprotozoal activities; in addition, important antiprotozoal effect was detected with kaempferol-3,7-dimethyl ether and 5-hydroxy-7-3′,4′-trimethoxyflavanone. The extract and the terpenoids possess good anti-inflammatory activity. The extract did not produce lethality or adverse effects in acute and sub-acute tests.