Anti-HIV activity of extracts from Hyptis radicans (Lamiaceae)

Abstract

Hyptis is a genus of Lamiaceae, comprising of approximately 144 species which are distributed in tropical and subtropical regions from North America to the Caribbean and southward to Argentina and Peru. Hyptis species are known to be used in folk medicine to treat various diseases such as flu and constipation (H. fruticosa), respiratory diseases (H. macrostachys), stomach and intestinal disorders (H. martiusii), colic and liver disease (H. pectinata), nasal and ear disorders (H. umbrosa) and fever (H. suaveolens) [1]. Hyptis species are aromatic and the essential oils have often been reported as responsible for many biological actions, but other compounds are also important, as diterpenes, lignans and some flavonoids (in most cases highly methoxylated). Hyptis radicans is a species from the Atlantic Forest, easily found in Paranapiacaba, SP, Brazil, and currently there is no literature describing its pharmacological potential. Therefore the anti-HIV1 potential of H. radicans extracts was investigated. The plant material was collected, dried at 40 °C for a week, powdered and subjected to maceration in ethanol for 7 days at room temperature in the dark. Aqueous extracts were obtained by boiling the plant material for 3h. Ethanolic crude extracts were fractionated using methanol and hexane. All samples were dissolved in DMSO 10% to achieve concentrations of 200, 500 and 1000 µg/ml for an anti-HIV1 assay (Roche®). Foscarnet (3 µg/ml) was used as a positive control. The sample that showed the highest percentage of RT-inhibition, expressed as MIC, was an aqueous extract (0.53 mg/mL) followed by methanol (0.69 mg/mL), hexane (0.78 mg/mL) and ethanol crude extracts (2.8 mg/mL). All extracts were analyzed by HPLC and GC-MS and the major compounds found were flavonoids, phenylpropanoids and their derivatives, even in the hexane fraction. According to the results, H. radicans is a promising species for the search for phenolic substances with anti-HIV1 activity.