Caracterização fitoquímica e antioxidante dos extratos hidroalcóolicos de Moringa oleífera Lam em diferentes épocas de coleta

Abstract

Moringa oleifera Lam is a tree vegetable, belonging to the moringaceae family, of Indian origin, cultivated mainly in places with dry tropical climates in various regions of the world. Due to its bioactivity, it has gained enormous attention in the last decade, which has led to increased exploration and understanding of its pharmacological functions and underlying mechanisms. The aim of this study was to characterize phenolic phytochemical compounds and antioxidant activity of hydroalcoholic extracts of Moringa oleifera Lam at different collection times. The collection of samples (powder and tea) was carried out at the Centro de Ciências Agrárias (CECA) from the Federal University of Alagoas (UFAL) in Rio Largo-AL (samples 2019) and in the village Sítio Salão in the municipality of Inhapi- AL. The samples were submitted to hydroalcoholic extraction. The methodology adopted includes Antioxidant activity (DPPH), determination of total flavonoids content (AlCl3), determination of total phenols (Folin-Ciocauteal), analysis of HPLC-DAD and LC- Orbitrap_ESI-FTMS. The DPPH radical scavenging capacity assay of the 2019 Powder samples showed good results with high antioxidant capacity for MO50% extract (>85%), followed by MO40% extract (>62%), MO30% extract (30.42%) and extract MO20% (21.33%), also being noticeable that the antioxidant capacity was concentration dependent. Samples of MO powder extracts collected in 2021 showed that extracts collected in June, July and August using a high percentage of alcohol (50% and 75%) during the extractive process showed an IC50 result of less than 50 µg/mL. The MO tea samples collected in 2021 consolidated the study of antioxidant activity, showing that hydroalcoholic extracts with a lower percentage of alcohol (MO25% tea extract) had lower antioxidant activity than the extracts with a higher percentage of alcohol used in the extraction (MO50% tea and MO75% tea). The MO powder samples showed higher antioxidant capacity than the MO tea samples. The MO powder samples exhibited significant total flavonoid contents between 1.14% and 2.35%, highlighting the months of June powder 50% with 2.35% and August powder 75% with 2.00%, 1, 14% August powder 50%, while the months of January and February showed values between 0.67% and 0.98% of total flavonoids, respectively.The analysis of the total phenol content showed a high content in the months of intense sunlight with values of 13.39% and 8.38% for the months of January and February, respectively; while the rainy months (June, July and August) showed minimal variation with values between 5.39% (July) and 5.78% (June). The LCMS assay using the analytical standards method identified the presence of acid flavonoids caffeic acid, 2-coumaric acid, umbelliferone, p-coumaric acid, vitexin, rutin, quercetin, kaempferol, luteolin, apigenin, pinocembrin at high intensities in samples of moringa extract February and July 75% powder. The LC-MS assay also detected the presence of isoquercitrin, quercetin 3-Omalonylglucoside (m/z 550.0927), kaempferol 3-O-(6´´- malonylglucoside) (m/z 489.1493) and kaempferol 3-O-glucoside (m/z 447.2616) known as astragalin based on scientific literature data. In general, the antioxidant activity and flavonoid content of MO powder extracts increased in the months of heavy rainfall (June, July and August), decreasing significantly in the months with low rainfall. While the total phenol content was higher in the months of intense sunshine and lower in the rainy months. The LC-MS data corroborate this information with lower values for ferulic acid and caffeic acid (February sample) and higher values for flavonoids (vitexin, rutin, quercetin, kaempferol, luteolin) in the July sample.