Acute oral toxicity studies of Swietenia macrophylla seeds in Sprague Dawley rats.

BACKGROUND: Swietenia macrophylla King. (Meliaceae) seeds (SMS); commonly known as sky fruit and locally known in Malaysia as Tunjuk Langit; have been used in traditional Malay medicine for the treatment of diabetes and hypertension. The people eat only a tiny amount of raw seed, weighing not more than 5 mg. AIM: To evaluate the safety of Swietenia macrophylla seeds (SMS) at a single-dose oral administration of 2 g/kg body weight (bw) in sprague dawley (SD) rats. MATERIALS AND METHODS: Eight-week old male and female SD rats were administered a single-oral dose of 2g/kg bw. The rats' general behavior, and toxic signs were observed throughout the 14-day study period. The food and water intake by rats and their body weight were monitored during the study period. At the end of the study period, the relative weights of the organs (lung, liver, spleen, heart, kidney, testis, stomach); the hematological and biochemical parameters were measured; the architecture and histology of the organs (liver, kidney and lungs) were observed. RESULTS: Oral administration of SMS to rats did not affect, either food or water intake; relative organ weight of vital organs; the hematological and biochemical parameters; did not show significant changes in the architecture and histology of vital organs. Overall, there were neither signs of toxicity nor deaths recorded during the study period. CONCLUSION: The rat dose of 2 g/kg bw is equivalent to the human dose of 325 mg/kg bw, which is well below the usual amount consumed by people, did not show any signs of toxicity in rats.

Salt stress-induced protein pattern associated with photosynthetic parameters and andrographolide content in Andrographis paniculata Nees.

Andrographis paniculata is a multifunctional medicinal plant and a potent source of bioactive compounds. Impact of environmental stresses such as salinity on protein diversification, as well as the consequent changes in the photosynthetic parameters and andrographolide content (AG) of the herb, has not yet been thoroughly investigated. The present study showed that the salinity affects the protein pattern, and subsequently, it decreased the photosynthetic parameters, protein content, total dry weight, and total crude extract. Exceptionally, the AG content was increased (p ≤ 0.01). Moreover, it was noticed that the salinity at 12 dS m(-1) led to the maximum increase in AG content in all accessions. Interestingly, the leaf protein analysis revealed that the two polymorphic protein bands as low- and medium-sized of 17 and 45 kDa acted as the activator agents for the photosynthetic parameters and AG content. Protein sequencing and proteomic analysis can be conducted based on the present findings in the future.

A classical genetic solution to enhance the biosynthesis of anticancer phytochemicals in Andrographis paniculata Nees.

Andrographolides, the diterpene lactones, are major bioactive phytochemicals which could be found in different parts of the medicinal herb Andrographis paniculata. A number of such compounds namely andrographolide (AG), neoandrographolide (NAG), and 14-deoxy-11,12-didehydroandrographolide (DDAG) have already attracted a great deal of attention due to their potential therapeutic effects in hard-to-treat diseases such as cancers and HIV. Recently, they have also been considered as substrates for the discovery of novel pharmaceutical compounds. Nevertheless, there is still a huge gap in knowledge on the genetic pattern of the biosynthesis of these bioactive compounds. Hence, the present study aimed to investigate the genetic mechanisms controlling the biosynthesis of these phytochemicals using a diallel analysis. The high performance liquid chromatography analysis of the three andrographolides in 210 F1 progenies confirmed that the biosynthesis of these andrographolides was considerably increased via intraspecific hybridization. The results revealed high, moderate and low heterosis for DDAG, AG and NAG, respectively. Furthermore, the preponderance of non-additive gene actions was affirmed in the enhancement of the three andrographolides contents. The consequence of this type of gene action was the occurrence of high broad-sense and low narrow-sense heritabilities for the above mentioned andrographolides. The prevalence of non-additive gene action suggests the suitability of heterosis breeding and hybrid seed production as a preferred option to produce new plant varieties with higher andrographolide contents using the wild accessions of A. paniculata. Moreover, from an evolutionary point of view, the occurrence of population bottlenecks in the Malaysian accessions of A. paniculata was unveiled by observing a low level of additive genetic variance (VA ) for all the andrographolides.

Andrographolide derivatives inhibit guanine nucleotide exchange and abrogate oncogenic Ras function.

Aberrant signaling by oncogenic mutant rat sarcoma (Ras) proteins occurs in ∼15% of all human tumors, yet direct inhibition of Ras by small molecules has remained elusive. Recently, several small-molecule ligands have been discovered that directly bind Ras and inhibit its function by interfering with exchange factor binding. However, it is unclear whether, or how, these ligands could lead to drugs that act against constitutively active oncogenic mutant Ras. Using a dynamics-based pocket identification scheme, ensemble docking, and innovative cell-based assays, here we show that andrographolide (AGP)--a bicyclic diterpenoid lactone isolated from Andrographis paniculata--and its benzylidene derivatives bind to transient pockets on Kirsten-Ras (K-Ras) and inhibit GDP-GTP exchange. As expected for inhibitors of exchange factor binding, AGP derivatives reduced GTP loading of wild-type K-Ras in response to acute EGF stimulation with a concomitant reduction in MAPK activation. Remarkably, however, prolonged treatment with AGP derivatives also reduced GTP loading of, and signal transmission by, oncogenic mutant K-RasG12V. In sum, the combined analysis of our computational and cell biology results show that AGP derivatives directly bind Ras, block GDP-GTP exchange, and inhibit both wild-type and oncogenic K-Ras signaling. Importantly, our findings not only show that nucleotide exchange factors are required for oncogenic Ras signaling but also demonstrate that inhibiting nucleotide exchange is a valid approach to abrogating the function of oncogenic mutant Ras.