HPLC analysis of camptothecin content in various parts of Nothapodytes foetida collected on different periods

Objective:To investigate the content of topoisomerase I-DNA inhibitor alkaloid camptothecin(CPT) from various parts of Nothapodytes foetida(N.foetida) collected from the month of October to February.Methods:The content of CPT was quantified in the methanolic extract of various parts of N.foetida using high performance liquid chromatography(UPLC).Quantification was performed with the regression analysis and the method was validated as per ICH guidelines. Results:The results revealed that maximum concentrations of camptothecin were found in root(2.62%) collected in the month of February followed by fruits(January,1.22%),stem(January,0.81%) and leaves(February,0.70%).Roots were found to have 3-fold higher concentration of CPT than the leaves and stem,while the fruits showed 2-fold higher concentration.Maximum concentration of camptothecin in fruits was observed in month of January,when they were not fully mature, which was 2-fold higher than that of young and fully mature fruits.Conclusions:These findings indicate that the synthesis of CPT differs in different parts of N.foetida and the content varies periodically.

Biological activities of silver nanoparticles from Nothapodytes nimmoniana(Graham)Mabb.fruit extracts

In the present investigation,we have described the green biosynthesis of silver nanoparticles(AgNPs)using ripened fruit aqueous extract of Nothapodytes nimmoniana(Graham)Mabb.as capping agent.The antioxidant,anticancer and antimicrobial activities of AgNPs were also studied.UV analysis revealed that AgNPs had a sharp peak at 416 nm.X-ray diffraction(XRD)result confirmed the characteristic peaks indicated at 111,200,220 and 311 for the crystalline of the face centered cubic silver.The Scanning Electron Microscopy analysis results confirmed the spherical shaped of AgNPs with difference sizes of the particles and an average from 44 to 64 nm.Further,fruit extract and AgNPs were evaluated total phenolic,tannin and flavonoid contents and were subjected to assess their antioxidant potential using various in vitro systems such as using 1,1-diphenyl-2-picryl-hydrazyl(DPPH),2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS),metal chelating,phosphomolybdenum and ferric reducing antioxidant power(FRAP)activities and antimicrobial activity against Bacillus subtilis,Pseudomonas aeruginosa,Klebsiella pneumoniae,Staphylococcus aureus and Escherichia coli.When compared to AgNPs,fruit extract exhibited uppermost radical scavenging activities.In addition,the cytotoxicity activity was determined by MTT assay.Our results clearly proved that biosynthesized AgNPs inhibited proliferation of HeLA cell line with an IC50 of 87.32±1.43g/mL and antibacterial activity.

Identification and characterization of camptothecin tailoring enzymes in Nothapodytes tomentosa

Camptothecin is a complex monoterpenoid indole alkaloid with remarkable antitumor activity.Given that two C-10 modified camptothecin derivatives,topotecan and irinotecan,have been approved as potent anticancer agents,there is a critical need for methods to access other aromatic ringfunctionalized congeners(e.g.,C-9,C-10,etc.).However,contemporary methods for chemical oxidation are generally harsh and low-yielding when applied to the camptothecin scaffold,thereby limiting the development of modified derivatives.Reported herein,we have identified four tailoring enzymes responsible for C-9 modifications of camptothecin from Nothapodytes tomentosa,via metabolomic and transcriptomic analysis.These consist of a cytochrome P450(Nt CPT9H)which catalyzes the regioselective oxidation of camptothecin to 9-hydroxycamptothecin,as well as two methyltransferases(Nt OMT1/2,converting 9-hydroxycamptothecin to 9-methoxycamptothecin),and a uridine diphosphate-glycosyltransferase(Nt UGT5,decorating 9-hydroxycamptothecin to9-β-D-glucosyloxycamptothecin).Importantly,the critical residues that contribute to the specific catalytic activity of Nt CPT9H have been elucidated through molecular docking and mutagenesis experiments.This work provides a genetic basis for producing camptothecin derivatives through metabolic engineering.This will hasten the discovery of novel C-9 modified camptothecin derivatives,with profound implications for pharmaceutical manufacture.

臭马比木茎段离体培养研究初报

以臭马比木(Nothapodytes nimmoniana)带芽茎段作外植体进行离体培养,研究了不同基本培养基和激素浓度对其侧芽萌发的影响。结果表明,基本培养基类型对臭马比木茎段外植体带芽茎段的萌发有极显著影响,以WPM作为基本培养基,侧芽萌发率和增殖系数极显著高于MS和B5培养基。正交试验结果显示WPM+0.5 mg/L TDZ+1.5 mg/L 6-BA最适于臭马比木茎段的离体培养,侧芽萌发率和增殖系数分别为96.8%和1.14。