Pharmacognostical investigations on the seeds and seed kernels of prunus mahaleb L. used as food and folk medicine

Prunus mahaleb L. (syn. Cerasus mahaleb L. Mill.), a member of medicinal plant kingdom, is known as mahlep, mehlep, idris ağac or pis agac and the seeds used as food and exported. In the present study, In our thesis, phytochemical and biological effects studies were carried out on P. mahaleb seed and seed kernels. The water:methanolic extract of the seed kernels (endocarp) applied to various chromatographic methods and as a result of the phytochemical studies 15 compounds were isolated, 1 of which is new, 11 compounds (2-O-β-glucopyranosyloxyl-4-methoxy-hydrocinnamic acid, cis-mellilotoside, dihydromellilotoside, trans-mellilotoside, 2-O-β-glucosyloxy-4-methoxy- trans-cinnamic acid, 2-hydroxy-4-metoxy hydrocinnamic acid, gallic acid, quercetin-3-O-(2-O,6-O-α-dirhamnopyranoside)-β-glucopyranoside, kaempferol-3-O-(2-O,6-O-α-dirhamnopyranosyl)- β-glucopyranoside), β-sitosterol 3-O-β-glucopyranoside and ursolic acid) were elucidated by advanced spectroscopic methods. Fungi tyrosinase enzyme inhibitions of the extracts and fractions obtained from the seeds and seed kernels (endocarp) of P. mahaleb with those of the compounds isolated from the seed kernels only were investigated. The enzyme kinetics of some of the active cinnamic acid derivatives were studied and their inhibition types and the Ki values, showing the linkage of the enzyme, were calculated. In order to evaluate their effects towards melanogenesis, a spectroscopic method was chosen and melanine content in B16F10 cells and their cellular tirosinase enzyme inhibitions were investigated to clarify the structure-activity relations. The scavenger activities of the extracts and fractions against DPPH, NO, SO, ABTS radicals and antioxidant capacities by using TEAC ve CUPRAC methods were determined. Their cytotoxic activities were investigated by L929 (mouse fibroblast), B16F10 (Mouse melanoma), A2058 (human melanoma) ve HeLa (human cervical carsinoma) cell lines. The extracts and the fractions which have strong antioxidant activity, showed a high dose dependent toxicity to melanoma cells but no toxicity to HeLa and L929 cells. The results made clear the selectivity of the cytotoxicity activity. Our thesis study showed that P. mahaleb seed kernels containing high effective skin whitening compounds have significant potential for the cosmetic industry. These results are important in terms of the fact that mahaleb kernels, which are still not used seriously, will add value economically after the seeds.