Phenolic compounds and anti-HIV1 potential of Merostachys neesii Rupecht (Bambusoideae)

Bamboos have great economical and medicinal importance. Brazil presents the greatest diversity of bamboos in the New World, with Merostachys Spreng. being the genus most representative in number of species. However, phytochemical and pharmacological studies with native species are scarce. This study aimed to evaluate the contents of phenolic compounds of leaves and culms from Merostachys neesii Ruprecht, an endemic Brazilian bamboo species, and their anti-HIV1 potential. Plant material was collected, dried at 40 °C, and powered. Vegetal material was extracted by maceration in 70% ethanol and by infusion. Leaf ethanol extract (LEE) and Culm ethanol extract (CEE) were partitioned resulting in four phases: hexane (P1), dichloromethane (P2), ethyl acetate (P3), and hydromethanolic (P4) phases. All extracts and phases were analyzed by high performance liquid chromatography (HPLC). Results were expressed as mg g^-1 equivalent to apigenin or chlorogenic acid. Extracts and phases were also tested against the HIV1 transcriptase reverse (RT) activity using a colorimetric kit (Roche Diagnostics) according to the manufacturer's instructions. Results were expressed in minimum concentration to inhibit 50% of RT activity (MIC₅₀). Culms showed higher flavonoids and phenolic acids contents than leaves. UV-visible spectra analyses revealed predominance of chlorogenic acid derivatives and flavones. For leaves and culms, P2 (3.98 and 17.88 mg g^-1) and P3 (16.43 and 18.73 mg g^-1) exhibited the highest contents of phenolic acids and flavonoids, respectively. Culm infusion extract showed the lower MIC₅₀ (844.05 µg mL^-1), followed by leaf infusion extract (1310.39 µg mL^-1). Although flavones and chlorogenic acids have been reported as substances with anti-HIV1 potential [1], M. neesii extracts and phases did not present anti-HIV activity. Isolation of the M. neesii phenolic constituents is in progress.

[1] Andrae-Marobela K, Ghislain FW, Okatch H, Majinda RRT. Curr Drug Metab 2013; 14: 392 – 413