ABSTRACT
Hymenocardia acida (HA) and Celosia trigyna (CT) are well-known medicinal plants used in the management of tumour-related ailments in South Western part of Nigeria. This work was carried out to examine this claim considering the fact that not many studies have been done to establish the ethno medicinal claim in relation to cancer management using bench top cytotoxicity models and human cancer cell lines.
Preliminary phytochemical screening of methanol crude extracts was done using standard methods. Bench-top cytotoxicity screening was carried out on the crude extract using Saccharomyces cerevisiae (20 – 100 µg/mL) and tadpoles of Raniceps ranninus (20 – 400 µg/mL), while growth inhibitory assay was carried out using Sorghum bicolor (SB) (1 - 30 mg/mL) model. Nanoencapsulation of HA extract was carried out while bioactivity-guided isolation of cytotoxic principle(s) was carried out on the two plants using combination of different chromatographic techniques. In silico study on isolated compounds was carried out using standard precision model of Schrödinger Suite. Anticancer effects of the extracts and compounds were evaluated on human breast (MCF-7), lung (H460) and colon cancer (HCT116) cell lines using Sulforhodamine B and (3-(4, 5dimethyl thiazol-2yl) - 2, 5-diphenyl tetrazolium bromide (MTT) assays. The compounds isolated were subjected to spectroscopic analyses to determine their identities.
Presence of steroids, terpenoids, glycosides, reducing sugars, flavonoids and phenolics were observed in the two extracts. Hymenocardia acida exhibited 100% mortality on the Raniceps ranninus (RR) at different concentrations (20 – 400 μg/mL), CT extract produced 100% mortality of Raniceps ranninus (RR) at 200 and 400 μg/mL, respectively. The two extracts produced significant (p<0.05) reduction in the radicle length of guinea corn (SB) in a concentration-dependent manner throughout the period of the experiment. At concentrations of 15.6 and 250 µg/mL, HA produced 71.70 ± 1.10 and 96.98 ± 1.96 % cytotoxicity against Saccharomyces cerevisiae, respectively whereas its aqueous fraction exhibited 93.90 ± 1.51 and 98.99 ± 1.96 % at 31.2 and 250 µg/mL, respectively. Celosia trigyna extract produced low cytotoxic activity at all concentrations but with improved activity upon solvent partitioning (C. trigyna aqueous fraction; CTA) at 125 and 250 µg/mL showing percentage inhibition of 88.00 ± 2.08% and 84.80 ± 1.62%, respectively. The extracts and their respective solvent fractions exhibited cytotoxic activities on all the cancer cell lines used. The most active fraction of HA produced lupeol, while CT produced spinasterol as active constituents. The compounds showed remarkable cytotoxic effects on the cancer cell lines at low concentrations.
This research justified the ethnomedicinal claim of Hymenocardia acida and Celosia trigyna in the treatment of tumour-related ailments. The anticancer effects of the plants are due to lupeol and spinasterol. Spinasterol is reported from CT for the first time.
