Estudo fitoquímico das folhas de Solanum stipulaceum Roem. & Schult. e composição, atividade biológica e efeito da radiação gama nos óleos essenciais obtidos a partir das suas flores e folhas

Abstract

The use of plants as herbal medicines and their derivatives has considerably increased in the last years, as well as the interest of general population, health agencies and pharmaceutical industries to ensure the microbiological and physicochemical quality. Among the microbial decontamination methods for plant materials, gamma radiation is one of the most efficient techniques. However, the high energy of this type of radiation can chemically change the plant material, affecting its chemical composition and biological properties. The species Solanum stipulaceum Roem & Schult (Solanaceae) is an endemic and native Brazilian plant, widely used by the population for therapeutic purposes, but it has not been well studied chemical and pharmacologically. In this context, the gamma radiation effect on the composition of essential oil from flowers and leaves of S. stipulaceum and its antioxidant andcytotoxic properties was evaluated. Initially, the study of the composition of essential oil from flowers was made, identifying -caryophyllene, -gurjunene, and -gurjunene as main components in flowers, collected in May, and -caryophyllene, caryophyllene oxide and - gurjunene in flowers collected in September. In the essential oil from leaves, -caryophyllene, -elemene, -spathulenol, caryophyllene oxide and -cadinol were identified as the major volatile compounds. The results obtained with the irradiated samples showed that flowers aremore susceptible to gamma-radiation, whereas, at a dose of 20.0 kGy, the composition of the most volatile compounds decreases significantly. Moreover, these essential oils did not show significant antileukemic activity. The composition of essential oil from leaves was unaffectedand this was associated with the presence of free radicals in the non-irradiated leaves. However, irregular changes were observed in the antioxidant and antileukemic activities of these oils. In addition, the phytochemical study of the hexane extract and dichloromethanefraction of the ethanol extract from leaves of S. stipulaceum was made and it allowed to identify the compounds -sitosterol, stigmasterol, farnesilfarnesol and bis (2-ethylhexyl) phthalate.