Investigação do potencial químico e farmacológico de Xylopia sericea A. St.-Hil. (Annonaceae)

Abstract

Xylopia sericea, Annonaceae, is a species native from Brazil, popularly known as "embiriba", "banana-de-macaco", "pindaíba", "pimento-de-macaco". Besides being used as condiment, the species is used in landscaping, in home rope factory and for medicinal purposes in the treatment of pain, inflammation, and gastrointestinal disorders. The aims of this study was to corroborate some of X. sericea medicinal use and to expand the chemical and biological knowledge on this species. For this, the fruits of X. sericea were extracted with methanol to obtain the methanolic extract (EBM), and also had its essential oil (OXS) extracted by hydrodistillation. The phytochemical study of EBM was conducted to identify the main classes of special metabolites and to determine of the contents of total phenols and flavonoids. OXS was characterized by GC-MS. In vitro, EBM and OXS were evaluated for the following activities: antioxidant by DPPH scavenging, β-carotene bleaching, and phosphomolybdenum assays; antibacterial by determining the MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration) for 10 strains of clinical importance; leishmanial for promastigote forms of L. amazonensis and L. chagasi; cytotoxic against the tumor cell lines Jurkat, HL-60, MCF-7, THP-1, MDA-231, HCT-116 and no tumor Vero cells. The in vivo anti-inflammatory activity was evaluated by the croton oil-induced ear edema method, orally (EBM) and topically (EBM and OXS). The acute toxicity of EBM and the median lethal dose (LD50) were determined. Phenols, flavonoids, coumarins, saponins, tannins, alkaloids and terpenoids/steroids were identified in EBM. The content of total phenols was 358.2 ± 33.1 mg/g expressed as equivalent to tannic acid and of flavonoids was 28.8 ± 8 2 mg/g expressed as equivalents to quercetin. Sixty three compounds were identified in OXS corresponding to 80 % of the oil constituents. Among them, spathulenol (16.42 %), guaiol (13.93 %) and germacrene D (8.11 %) were the major. Regarding the antioxidant activity, EBM and OXS presented by the DPPH method, IC50 of 16.37 and 49.16 μg/mL, respectively; IC50 of 49.16 and 6.92 μg/mL by β-caroten bleaching method; 0.75 mg/mg of EBM and 2.30 mg/mg of OXS equivalents to ascorbic acid by phosphomolybdenum method. Results for antibacterial activity showed that the most sensitive strains to EBM were S. aureus, E. cloacae and B. cereus with MIC of 7.8; 7.8 and 31.25 μg/mL, respectively. To OXS, S. aureus, E. cloacae, K. pneumoniae and B. cereus showed the highest sensitivity with MIC of 7.8; 7.8; 62.5 and 15.63 μg/mL, respectively. Furthermore, it was observed that EBM and OXS showed bactericidal activity for E. faecalis (1000 μg/mL) and B. cereus (31.25 μg/mL), respectively. Regarding leishmanicidal activity, EBM showed IC50 of 42.51 μg/mL for L. amazonensis, but showed no activity against L. chagasi. Moreover, OXS was evaluated only for L. amazonensis and showed no activity. EBM was able to inhibit cell proliferation by 56% for HL-60 and showed no significantive toxicity to the other tumor cells, and also Vero cells. Topical application of EBM reduced the ear edema caused by croton oil by 41.8 %, 99.1 % and 56.9 % at doses of 1; 0.5 and 0.1 mg/ear. OXS was able to reduce the edema at the doses of 1 and 0.5 mg/ear by 43.4 % and 54.2 %. Orally, EBM was able to reduce the edema at doses of 300, 100 and 50 mg/kg by 36.3 %, 29.5 % and 32.0 %. No signs of toxicity were observed for EBM, with an LD50 > 2000 mg/kg. The results are relevant since EBM and OXS showed promising biological activities which justifies the continuation of the study.