Rat MAPK3 blocking peptide

Objective: To investigate bioactive phytochemicals and antioxidant activities of Nymphaea nouchali and to explore its anticancer pathways by a network pharmacology approach. Methods: Using a spectrophotometer and high-performance liquid chromatography-diode array detector (HPLC-DAD), we quantified bioactive phytochemicals in methanolic extract of Nymphaea nouchali tuber. The extracts were investigated for in vitro antioxidant properties. Targets of these bioactive phytochemicals were predicted and anticancer-associated pathways were analyzed by a network pharmacology approach. Moreover, we identified the predicted genes associated with cancer pathways and the hub genes in the protein-protein interaction network of predicted genes. Results: Quantitative results indicated the total phenolics, total flavonoids, and total proanthocyanidins in the methanolic extract of Nymphaea nouchali tuber. HPLC-DAD analysis showed rutin (39.44 mg), catechin (39.20 mg), myricetin (30.77 mg), ellagic acid (11.05 mg), gallic acid (3.67 mg), vanillic acid (0.75 mg), rosmarinic acid (4.81 mg), p-coumaric acid (3.35 mg), and quercetin (0.90 mg) in 1 g of dry extract. The extract showed the radical scavenging activities of 2, 2-diphenyl-1-picrylhydrazyl, 2,2'-azino- bis (3-ethylbenzothiazoline-6-sulfonic acid) and N,N-dimethyl-p phenylenediamine. By using network pharmacology, we predicted 130 target genes associated with cancer pathways. The top hub genes (IL6, AKT1, EGFR, JUN, PTGS2, MAPK3, CASP3, and CXCL8) were also identified, which were associated with cancer pathways and interacted with bioactive phytochemicals of the methanolic extract of Nymphaea nouchali tuber. Conclusions: Our study provides insights into the mechanism of anticancer activities of the methanolic extract of Nymphaea nouchali tuber.

Participation and relative importance of phosphatidylinositol-3 kinase (PI3K) and mitogen-activated protein kinase (MAPK) signalling, either alone or in combination, have been investigated during 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (DHP)-induced meiotic G2-M1 transition in denuded zebrafish oocyte. Results demonstrate that concomitant with rapid phosphorylation (activation) of Akt (Ser473) and MAPK (ERK1/2) at as early as 15 min of incubation, DHP stimulation promotes enhanced an GVBD response and histone H1 kinase activation between 1 and 5 h in full-grown oocytes in vitro. While p-Akt reaches its peak at 60 to 90 min and undergoes downregulation to the basal level by 240 min, ERK1/2 phosphorylation (activation) increases gradually until 120 min and remains high thereafter. Although, priming with MEK1/2 inhibitor U0126 is without effect, PI3K inhibitors, wortmannin or LY294002, delay the GVBD response significantly (P < 0.001) until 3 h but not at 5 h of incubation. Interestingly, blocking PI3K and MEK function together could abrogate steroid-induced oocyte maturation at all time points tested. While DHP stimulation promotes phospho-PKA catalytic (p-PKAc) dephosphorylation (inactivation) between 30-120 min of incubation, simultaneous inhibition of PI3K and MEK1/2 kinases abrogates DHP action. Conversely, elevated intra-oocyte cAMP, through priming with either adenylyl cyclase (AC) activator forskolin (FK) or dibutyryl cAMP (db-cAMP), abrogates steroid-induced Akt and ERK1/2 phosphorylation. Taken together, these results suggest that DHP-induced Akt and ERK activation precedes the onset of meiosis (GVBD response) in a cAMP-sensitive manner and PI3K/Akt and MEK/MAPK pathways together have a pivotal influence in the downregulation of PKA and resumption of meiotic maturation in zebrafish oocytes in vitro.