Estudo químico-biológico das espécies Coutarea hexandra (Rubiaceae) e Annona rugulosa (Annonaceae)

Abstract

Plants represent an important source of natural products with an big structural diversity and chemical-biological properties. Coutarea hexandra (quina-quina) is a species of the Rubiaceae family, in folk medicine, its aqueous extract is used in combating pain, inflammation, as diuretic and abortifacient. As for the chemical profile, it is reported that triterpenes/steroids, flavonoids, polyphenols, condensed tannins, alkaloids and coumarins. Annona rugulosa (anona) is a species of the Annonaceae family, its leaves have already demonstrated significant antiproliferative activity on HeLa cells. Its chemical profile is made up of steroids, alkaloids and acetogenins. Thus, this work describes the chemical constituents, antioxidant potential, total flavonoid content and toxicity of the species Coutarea hexandra (Rubiaceae) and Annona rugulosa (Annonaceae) in order to contribute to the chemical-biological knowledge of the same. The procedure consisted of performing Thin Layer Chromatography (TCD), phytochemical tests, acid-base extraction, Column Chromatography (CC), Preparative Chromatography (PC), evaluation of total flavonoid content, antioxidant activity by the free radical scavenging method (DPPH•) and toxicity against Artemia salina. The CCD suggested the presence of flavonoids, terpenoids, sugars and coumarins. Phytochemical tests for C. hexandra showed the presence of phlobatenic tannins, chalcones and aurones, quinones, free steroids, saponin heterosides, alkaloids and coumarins stood out. For A. rugulosa the classes of tannins, phlobatenics, flavonols, saponinic heterosides, alkaloids and coumarins stood out. The EECQ (stem/quina-quina), EEFQ (leaves/quina-quina), EECA (stem/anona) and EEFA (leaves/anona) extracts showed total flavonoid content equal to 61.38 ± 0.11; 146.96 ± 1.01; 27.08 ± 0.58 and 105.44 ± 2.11 (mg RE/g extract), respectively. The antioxidant activity (AA%) for EEFQ (250 µg.mL-1 ) was considered strong, as it presented AA% of 75.966 ± 5.59 and EC50 of 144.20 µg.mL-1 ± 21.63. The extracts EECQ (CL50 = 4168.69 μg.mL-1 ), EEFQ (CL50 = 80005.71 μg.mL-1 ) and EEFA (CL50 = 1570.36 μg.mL-1 ) were considered nontoxic, while EECA showed moderate toxicity (LC50 = 199.75 μg.mL-1 ). Acid-base extraction from EECQ and EECA esit provided substances 1 (10.2 mg), 2 (27.2 mg) 3 (11.4 mg). Qualitative analyses by CCD of these substances suggest the identification of a phenolic compound (flavonoid or coumarin), a terpene and another coumarin, respectively.