Role of Chitosan-Loaded Solanine Glycoalkaloid from Solanum scabrum Mill. Leaf Extract as Anti-Inflammatory and In Vitro Anticancer Agents.

Objectives: Solanum scabrum Mill. commonly "African nightshade" or "huckleberry" is a plant, whose leaves are used by tribes in Nigeria and Cameroon for making the popular "Kombi" and "Njama Njama" soups, respectively. This study aimed to evaluate the anti-inflammatory and anticancer activities of the leaf crude methanol extract from S. scabrum.

Materials and methods: Fractions of the plant were tested for anti-inflammatory potential and in vitro anticancer activity on MCF-7 and HMVII cell lines by carrageenan-induced oedema in mice, and cytotoxicity assays such as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide, transwell migration and invasion assays, and apoptosis study by flow cytometry, respectively.

Results: Bioguided isolation yielded a white crystalline compound 3-nitro dibenzofuran (C₁₂H₇NO₃, m/z; 213.19 g/mol, m.p.; 181.49 °C). ¹H-NMR showed seven signals at δ (ppm) 2.8-4.3 consisting of two doublets and five singlets, while ¹³C-NMR revealed twelve carbons, which are majorly methyl carbons at δ (ppm) between 120 and 195. All tested samples demonstrated dose-dependent anti-inflammatory activity in carrageenan-induced mice. The isolated compound, i.e. solanine, and chitosan-loaded drugs showed significant inhibitory activity on the cell lines with inhibitory concentration 50 (IC₅₀) values of 8.52, 0.82, and 22.1 μg/mL, respectively on MCF-7 cell line and 4.54, 0.08, and 12.1 μg/mL, respectively, on HMVII cell line, while doxorubicin (adriamycin) positive control, had IC₅₀ values of 0.02 and 0.06 μg/mL, respectively, on MCF-7 and HMVII cancer cells. Selectivity index of solanine was the lowest in the study, hence, it lacks the ability to differentiate between cancerous and normal cell Vero E6 cell lines. Chitosan-loaded drugs quicken early apoptosis and sustained late apoptosis in cells with much improved selective indices.

Conclusion: The results obtained from this study further affirmed the use of chitosan nanoparticles as carriers for anticancer drugs.