ABSTRACT
Plants containing bioactive substances have increasingly become the object of research studies, particularly those plants with therapeutic value. Many species of the genus Alpinia provide a variety of medicinal properties, such as, Alpinia zerumbet (Pers.) Burtt et Smith and A. purpurata (Vieill) K. Schum, which have a significant presence in Brazil. These species have been commercialized in the food and cosmetic industries. However, their greatest importance arises from the medicinal properties of their essential oils containing flavonoids, terpenoids and kavalactones which have been used in folk medicine to treat, for example, arterial hypertension and inflammatory processes. In addition, such species are also used in multidisciplinary studies, including phytochemistry, ethnobotany and biology, indicating the key pharmacological role of this genus in everyday life. Therefore, this work aims to present a bibliographic review of the genus Alpinia and its significance in therapeutic applications.
ABSTRACT
Leaf oil prepared by hydrodistillation of Alpinia zerumbet Pers.) B.L. Burtt & R.M. Sm. was analyzed by GC/FID and GC/MS to determine the major compounds and it was also evaluated for antimicrobial activity. The oil presented a high content of oxygenated monoterpenes (52.5 percent), terpinen-4-ol, 1,8 cineole and γ-terpinene as the major constituents. The antimicrobial activity of leaf oil was tested by drop diffusion and bioauthography methods. Through drop test, all bacteria and fungi tested were inhibited by leaf oil. Preparative TLC (thin-layer chromatography) plates were developed using the mobile phase hexane: ethyl acetate (70:20, v/v) and fractions of the leaf oil were separated in three zones, scraped, extracted from silica and identified by GC/MS. The bioauthography method permitted to verify pronounced inhibition of Cryptococcus neoformans by fractions F2 and F3, both rich in oxygenated monoterpenes. The fraction F2 comprised 1,8 cineole (9.6 percent), linalool (3.7 percent) and caryophyllene oxide (5.4 percent), while fraction F3 showed mainly terpinen-4-ol (43.6 percent) and an amount of 32.7 percent oxygenated sesquiterpenes. The obtained data may be used to suggest the constituents of A. zerumbet leaf oil involved in antimicrobial activity.
O óleo essencial de folhas de Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Sm., extraído por hidrodestilação, foi analisado por CG/DIC e CG/EM a fim de se determinar sua composição e atividade antimicrobiana. O óleo apresentou um elevado teor de monoterpenos oxigenados (52,5 por cento): terpinen-4-ol, 1,8-cineol e γ-terpineno como principais constituintes. A atividade antimicrobiana do óleo foi analisada pelos testes de difusão em agar e ensaios de bioautografia. Através do teste de difusão em agar, todas as bactérias e fungos testados foram inibidos pelo óleo essencial. Placas preparativas de CCD (cromatografia em camada fina) foram eluídas em hexano: acetato de etila (70:20, v/v), e o óleo foi separado em três frações que foram raspadas, extraídas da sílica e identificadas por CG/EM. A análise bioautográfica permitiu detectar pronunciada inibição de Cryptococcus neoformans pelas frações F2 e F3, ambas ricas em monoterpenos oxigenados. A fração F2 apresentou 1,8 cineol (9,6 por cento), linalol (3,7 por cento) e óxido de cariofileno (5,4 por cento), enquanto a fração F3 mostrou principalmente terpinen-4-ol (43,6 por cento) e cerca de 32,7 por cento de sesquiterpenos oxigenados. Os dados obtidos indicam os componentes do óleo de A. zerumbet envolvidos na atividade antimicrobiana.