Physico-chemical study of steroids from different matureness corn silk material

This study shows an ultrasonic assisted extraction procedure of steroids from corn silk (CS). The total steroids contents were positively correlated with the ultrasonic assisted extraction time. The extracted steroids contents varied according to the different maturity stages of CS. There were three tested CS maturity stages: silking stage (CS-S), milky stage (CS-M) and mature stage (CS-MS). The β - sitosterol standardization method with 530 nm wavelength colorimetric measurements were applied to determine the content of extracted steroids. Measured steroids concentrations range were from 38.3 × 10-3 mg.mL-1 to 368.9 × 10-3 mg.mL-1 in different extraction time and CS maturity stages. The highest concentration of steroids, 368.9 × 10-3 mg.mL-1 was found in CS-MS sample with the 75 minutes ultrasonic extraction time. The fluorescence mapping techniques were used to confirm the existence of steroids. The thermal analysis illustrated a typical multistep decomposition process for the CS-S, CS-M and CS-MS samples. Two endothermic peaks were found: The first one was 54.3 °C for CS-S and CS-MS, 60.2 °C for CS-M, the second one, 397 °C (CS-MS), 415.1 °C (CS-M) and 419.7 °C (CS-S) attributed to the total thermal decomposition. The observed exotheric process found at 524 °C corresponded to CS-MS sample decomposition. The optimal ultrasonic-assisted extraction time for all samples under study CS-S, CS-M and CS-MS was about 75 minutes and the optimal steroids extraction contents obtained were 92.8 × 10-3 mg.mL-1 (CS-S), 124.2 × 10-3 mg.mL-1 (CS-M) and 368.9 × 10-3 mg.mL-1 (CS-MS) respectively.

Physico-chemical study of flavonoids from different matureness corn silk material

There was tested a simple extraction procedure of flavonoids separation from the original corn silk (CS) material. It was found, that the total flavonoids content differs with the extraction time and extraction temperature. There were found different flavonoids contents in extracts prepared from different maturity stages of the original corn silk material (silking stage (CS-S), milky stage (CS-M)). Extracted flavonoids content was quantified by the lutin standardization method by means of colorimetry at 510 nm wavelength. Obsreved flavonoids concentration was ranging from 2×10-3 mg.mL-1 to 7 ×10-3 mg.mL-1 dependent on the extraction time period and extraction temperature. The highest flavonoids concentration of 7.5×10-3 mg.mL-1 was found for CS-M after 20 minutes extraction time and 80  °C extraction temperature. There was confirmed the presence of flavonoids by fluorescence mapping experiments. There was found a typical multistep decomposition process for both CS-S and CS-M materials by TG analysis. There was found a melting temperature of flavonoids of 54.3 °C for corn silk silking stage material exhibiting 58.9 J.g-1 heat of fusion and 60.2 °C for corn silk milky stage material with 112.9 J.g-1 heat of fusion. The optimal conditions of corn silk flavonoids extraction were 40 ℃, 50 minutes for CS-S, the optimal flavonoids extraction content was (6.8 ±2.1)×10-3 mg.mL-1, 80℃, 20 minutes for CS-M and the optimal extraction content was (7.2 ±0.3)×10-3 mg.mL-1.