Biological studies and chromatograms aided by chemometric analysis in evaluation of seasonality and extraction method of Croton grewioides extracts

The genus Croton is the second largest genus of Euphorbiaceae family, comprising more than 1300 registered species. The species Croton grewioides is endemic in the northeast of Brazil and distributed mainly throughout the caatinga biome presenting, in its essential oils, various compounds with biological activities such as pupicidal, larvicidal, insecticidal, and bactericidal. The secondary metabolites commonly found in their extracts include diterpenes, phenols, steroids, and aglycone and glycoside flavonoids derivatives, which can undergo variations based on climatic changes that modify processes such as photosynthesis, transpiration and nutrient cycle. To understand the effects of seasonal variability and extraction method on the biological activities of polar extracts from C. grewioides , fingerprint chromatograms were analyzed aided by chemometric analysis. In vitro assays of cytotoxicity against HL-60 and HepG2 cancer cells and anti-acetylcholinesterase activity were performed. Seasonal effects could only be observed in the chemical profiles of the methanolic and ethanolic extracts from accessions 113 and 126, respectively. Considering the extraction method, the chromatograms of aqueous and hydroalcoholic extracts of all the accessions were similar, but differed from those for the corresponding methanolic and ethanolic extracts. Five hexane partitions were active against HL-60 cell line, displaying inhibition values between 81 and 93%. Only the ethanolic extract of accession 101 (winter), the methanolic partition from the methanolic extract, and the decoction of accession 113 (winter) presented high inhibition values against the acetylcholinesterase enzyme. This study enabled elucidation of the effects of seasonality and extraction method on the biological activities presented by the C. grewioides extracts.