Simultaneous determination of four sesame lignans and conversion in Monascus aged vinegar using HPLC method.
A simple, accurate and specific high-performance liquid chromatography (HPLC) method has been developed and validated for simultaneous determination of sesamol, sesamin, asarinin and sesamolin in Monascus aged vinegar. The effects of acid hydrolysis and four heating treatments on the components content in Monascus aged vinegar were discussed. The results showed that the isomerisation of sesamin to asarinin, and decomposition of sesamolin to sesamol significantly increased, regardless of heating or acid hydrolysis. Thermal processes and acid hydrolysis increased the content of sesamol and asarinin, respectively, but severe thermal processes resulted in the loss of total sesame lignans. Sesamol and asarinin reached the highest (2.720 ± 0.202 μg/mL and 2.064 ± 0.075 μg/mL) for autoclaving (125 °C, 15 min) and acid hydrolysis (25 °C, 15 min, nature pH), respectively. Therefore, autoclaving and acid hydrolysis were considered as the optimal way to obtain higher content of sesamol and asarinin.
HPLC Analysis of Seed Sesamin and Sesamolin Variation in a Sesame Germplasm Collection in China
Sesame lignans, including mainly sesamin and sesamolin, has been reported to have multiple functions beneficial to health. This study analyzed sesamin and sesamolin contents by HPLC in 215 sesame lines from a core collection in China. The results showed the core sesame germplasm in China has a broad variation from 2.49 to 18.01 mg/g with average 8.54 mg/g in total of sesamin and sesamolin. On average, sesamin contents in the lines with a white seed coat color were significantly higher than in those samples with brown, yellow and black colors (P < 0.01). The lines with a black seed coat had the highest coefficient of variation followed by those with brown, yellow and white seed coats. The correlation coefficient between sesamin and sesamolin in the sesames with different seed coat colors ranked as white (R = 0.23) < yellow (R = 0.44) < brown (R = 0.72) < black (R = 0.77). The results of this study provide valuable background information on sesame germplasm in China and identified potential genotypes for breeding high sesamin or sesamolin cultivars.
Mesozoic rifting and basin inversion along the northern African Tethyan margin: an overview
Abstract The northern African Tethyan margin registered three major rifting episodes from the latest Palaeozoic-earliest Mesozoic to the earliest Cenozoic. Break-up of Gondwana was initiated in the late Carboniferous. Along the northern African-Arabian plate margin rifting propagated westward from the northeastern Arabian margin to Morocco during the Permian and Triassic, and was accompanied by Mid-Late Triassic-earliest Liassic extensive alkaline flow basalts. Rifting continued during the Liassic, e.g. in the Moghrebian Atlas troughs. A second stage of rifting occurred in the Late Jurassic and continued into, or was rejuvenated during, the Early Cretaceous. Along the east Mediterranean margin, some large E-W trending rifts formed, often with associated volcanism, e.g. southern Sirt and Abu Gharadig. Most researchers believe the oceanization of the eastern Mediterranean basin occurred at this time. Flexural subsidence affected the Moghrebian Atlas, including the Riffian-Tellian domain, where a thick flysch series was deposited. Two short-lived, but widespread and tectonically important, compressional or wrench-dominated events occurred during the Santonian and the latest Maastrichtian. From Morocco to Oman, most sedimentary basins were folded and inverted at these times. The Santonian event resulted from onset of the collision between the African-Arabian and Eurasian plates. New stress-fields favoured NE-SW extension along the African plate margin, generating or rejuvenating some rifts, e.g. in the Euphrates trough and in the Libya-Tunisia region (northwestern Sirt, Pelagian Sea). Rifting and magmatism continued in these regions into the Paleocene. During the Mesozoic, therefore, the northern margin of the African-Arabian plate registered both rifting resulting in the oceanization of the Tethys and rifting resulting from the initiation of the closure of the Tethys. The intraplate domain exhibited echoes of the tectonic events affecting the margin.