Rhododendron arboreum of the family Ericaceae represents one of the ancient relict tree species of the genus showing extreme disjunction in the Indian subcontinent. It is represented by two sub-species viz., ssp. arboreum Smith in the forests of north-eastern India (temperate) and spp. nilagiricum (Zenker) Tagg distributed in the southern Western Ghats (tropical) of India with apparently no distribution in the intervening plains. 35 Samples corresponding to different locations in the tropical montane forests of Nilgiris and temperate forests of northeast India were analyzed for distribution of genetic variation using 25 random primers. Relatively high genetic diversity was measured in the temperate populations (Ht = 0.21; Nm = 1.13) than tropical Rhododendrons. The hierarchical analysis of molecular variance showed that among the total variance, 25% is residing within populations while 63% of variance is among regions apparently revealing that disjunct distribution has structured genetic differentiation pattern in this species. Grouping of samples was in conformity with their spatial distribution, which was confirmed by UPGMA cluster analysis and PCA scatter plot. The taxon with its unique distribution pattern and wide cross compatibility between sub-species is however threatened by low genetic variation and gene flow that catalyses it's shifting towards genetic drift and hence long-term conservation strategies need to be formulated particularly for the tropical Rhododendron sub-species. Among the various hypotheses and theory proposed to explain the Malayan affinity in the flora and fauna of Western Ghats, Satpura hypothesis based on dispersal model of distribution largely explains the discontinues distribution of R. arboreum.
Morinda umbellata L. is a woody climber or liana distributed in south East Asia. It is a traditional medicinal plant with excellent curative effects against diarrhea, dysentery, and other stomach disorders. The present study was aimed to assess the effect of M. umbellata active fraction (MUAF) on various inflammatory mediators using lipopolysaccharide (LPS) induced in vivo model in Wistar rats. The effect of MUAF on secretion of TNF-α, IL-1β, and IL-6 were evaluated in LPS-induced experimental animals. The expression of TNF-α, IL-1β, IL-6, iNOS, COX-2, and nuclear factor NF-κB genes were also evaluated. The gas chromatography–mass spectrometry (GC–MS) analysis of the active fraction was carried out to identify the active compounds present in MUAF. The results of oral acute toxicity suggested the non-toxic nature of MUAF. GC–MS analysis of the MUAF leaves revealed the presence of 8 compounds. The study demonstrated that the proinflammatory cytokines such as TNF-α, IL-1β, and IL-6 were significantly inhibited by MUAF in a dose-dependent manner. Moreover, MUAF down-regulated the expression of TNF-α, IL-1β, IL-6, iNOS, COX-2, and NF-κB genes. Our research findings suggest that the presence of anti-inflammatory compounds in MUAF can effectively inhibit LPS-induced proinflammatory cytokines TNF-α, IL-β, and IL-6 in vivo. It also suppressed the over expression of TNF-α, IL-1β, IL-6, iNOS, and COX-2 possibly via downregulating NF-κB activation.
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