Background: In the present study a statistical model (Response Surface Methodology) was proposed for optimization of siderophore production by using Enterobacter hormaechei.Methods: The rhizospheric soil was used for isolation and isolates were screened for siderophore production by chrome-azurol S (CAS) assay. One potent isolate producing maximum siderophore was selected and characterized by 16S rRNA gene sequencing. The culture conditions were optimized for maximum siderophore production by using Central Composite Design. The response surface curves were used to predict the optimum levels of the factors affecting the yield of siderophore. Result: By using rhizospheric soil,eight isolates were obtained and one potent organism was identified as Enterobacter hormaechei subsp. oharae (Accession No. MT 775835) by BLAST. The maximum siderophore production (98%) was obtained in succinate medium and the optimum values of variables were found as pH 7, time 60 hrs, temp. 28°C and succinic acid conc. 0.40%. RSM was used to analyze the data by developing 3D surface plots and the residuals plots. ANOVA was used to determine regression coefficients.

Mashi is a black colored powder formulation obtained after combustion of the plant or animal drug. It is prepared by bahirdhum padhati (outside) or anterdhum padhati (in the close vessel). In this dosage form, bulk of raw material is reduced to a greater extent by the application of a certain quantum of energy. Due to this treatment, hidden chemical constituents become prominent and/or a new chemical moiety is formed which is therapeutically active. This formulation is cost-effective and easy to prepare. This review article aims to highlight the different mashi formulations mentioned in Ayurvedic text and also incorporate the formulation not mentioned in the Ayurvedic text but used by Ayurvedic practitioners. The objective was to introduce researchers to the simple yet excellent formulation mashi which should be studied in detail to establish its identity, purity, and therapeutic activity.