American International Journal of Biology and Life Sciences 2020-06-04T22:15:41+06:00 Executive Editor Open Journal Systems Ecological Mechanism of Dinosaur Extinction 2020-06-04T22:15:41+06:00 Huai Tang Gu <p>To analyze the reasons for the extinction of dinosaurs by applying the elimination methods, to exclude the factors that could not cause the worldwide extinction of the dinosaurs. At last obtain a conclusion that because the Ice Age had come on the Earth and caused the changing of climate that it had been becoming cold and arid from warmth and moist, and caused the <a href=";wd=&amp;eqid=ce59c5db00303363000000045e6bb98c">phyto-group</a> had been changing, which the Pteridophyte and gymnosperm groups fell off or died out, but the angiosperm groups had been developing and expanding. The characters of photosynthesis of producers of the biosphere had been becoming to the seasonal and regional from the perennial and global, the total of oxygen had reduced sharply in the atmosphere, the density of oxygen had declined, and finally affected the breath of dinosaurs, and led to the extinction of dinosaurs. And as the main producers of biosphere, the pteridophyte and gymnosperm groups had fallen off or died out were the mainly reasons for the creature’s extinction at the later of the Cretaceous period.</p> 2020-03-19T15:34:23+06:00 ##submission.copyrightStatement## Antioxidant Potential of Morinda Lucida and Psidium Guajava Extracts and Actions Against Paracetamol- Induced Kidney and Liver Injuries in Rats 2020-06-04T22:15:41+06:00 Fakoya Akindele Fredrick O. Obi <p>Antioxidant agents of plants origin have continued to attract interest because of the potential they hold in the maintenance of human health accompany with their minimal side effects. The present study sought to evaluate the comparative free radical scavenging activities of ethanol extracts of air dried <em>Morinda lucida</em> leaves (EMLL) and <em>Psidium guajava</em> leaves (EPGL) by measuring their ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, nitric oxide (NOˉ) radical, 2,2 azinobis-( 3-ethylbenzothiazoline-6-sulfonic acid) (ABTS*), and inhibit lipid peroxidation (LPO). Antioxidant activities of the extracts were also determined in the plasma of the rats fed with the extracts by assaying for antiradical activity against DPPH and NO radicals <em>in vitro</em>. <em>In vivo</em> antioxidant effects of the extracts were also evaluated in paracetamol treated rats. Twenty rats were randomly divided into four groups for this study. Group 1 received normal feed as control, group 2 received 14.30mg/kg b.w of paracetamol by gavage, groups 3 and 4 received 400mg/kg b.w of EMLL and EPGL each for 7 days plus paracetamol on the 8<sup>th</sup> day respectively. Catalase (CAT) and superoxide dismutase (SOD) activities and malondialdehyde (MDA) status were assayed for in the kidney, liver and serum. Histopathological examinations of liver and kidney were also carried out. The results showed that EMLL and EPGL exhibited free radical scavenging ability in dose dependent manner towards DPPH, NO, ABTS radicals as well as inhibition of LPO. The results of evaluation of the antioxidant potentials of the extracts while in the plasma showed that they were associated with free radical scavenging activity <em>in vivo</em>. Paracetamol treatment caused significant (p&lt;0.05) decreases in SOD and CAT activities, and marked increase (p&lt;0.05) in MDA levels when compared with the control. However, compared with paracetamol only group, the extracts caused significant (p&lt;0.05) increase in SOD and CAT activities and decreased MDA levels. Histopathological analysis of kidney and liver showed that the extracts were able to offer protection against paracetamol-induced kidney and liver injuries. The extracts therefore have strong antioxidant and cytoprotection abilities.</p> 2020-03-19T15:43:35+06:00 ##submission.copyrightStatement##