Ghansham Dixit’s research while affiliated with Shivaji University and other places

The flower color of Delphinium cultivars depends on the pigmentation with anthocyanins produced and their accumulation affecting the appearance. We first examinedthe flower color mutants of D. malabaricum obtained from ethyl methane sulfonate (EMS), sodium azide (SA), and gamma irradiation treatment with an idea that the analysis of anthocyanins is necessary in order to understand flower color variations in the mutants. In this view, we analyzed the content of delphinidin in flower color mutants of Delphinium by reversed phase high performance liquid chromatography (RP-HPLC) and discussed the relationship between delphinidin content and the flower color. The flower color mutants which ranged in color from blue to pale pink revealed a marked difference in the delphinidin content, the quantity of delphinidin differed in the respective mutants as compared with the parent cultivar. Color intensity was positively correlated with delphinidin content, the concentration of delphinidin varied from 0.130 mg/g to 8.207 mg/g of sample in pale pink and dark blue color mutants respectively with delphinidin content 6.668 mg/g in the traditional blue cultivar. Thus we provide evidence indicating that

The study aimed to develop an efficient, rapid, and large-scale in vitro regeneration system for propagation, conservation, and restoration of an endemic and critically endangered herb, Ceropegia mohanramii. The cultures were established using nodal explants on Murashige and Skoog’s (MS) medium supplemented with 6-benzylaminopurine (BAP: 1.0 mg/l). Nodal buds cultured on MS medium supplemented with BAP (2.0 mg/l) along with indole-3-butyric acid (IBA, 0.5 mg/l) resulted with production of maximum number of shoots (17.1 ± 1.2) in hundred percent of the cultures. MS medium supplemented with BAP (2.0 mg/l) along with diverse concentrations of indole-3acetic acid (IAA) promoted the in vitro flowering. In vitro regenerated shoots were transferred to one-half MS medium fortified with singular supplementation of auxins, where IBA (1.5 mg/l) served optimal for production of maximum number of roots (5.7 ± 0.6). In vitro derived plantlets were hardened under controlled conditions in a glasshouse and subsequently transferred to soil. Over 1200 saplings were transplanted to eight different localities of the Western Ghats where over 76% survival is recorded after 1 year of transplantation.

A systematic search of some phytochemicals in Delphinium malabaricum will be undertaken to evaluate the therapeutic quality of D. malabaricum. The populations of D. malabaricum were subjected to analysis of alkaloids by Reversed phase HPLC technique. Among the various alkaloids present in Delphinium species methyllycaconitine is a principle alkaloid. Therefore, the populations of D. malabaricum were assessed for Methyllycaconitine (MLA) content in the mutants and their control. The results revealed that the MLA content was highest with 0.01% concentration of EMS (0.78 mg/g plant material) as compared to the control (0.76 mg/g plant material). The concentration of MLA decreased with an increase in dose/concentration of the mutagens. Less concentration of MLA in the roots of D. malabaricum indicates that it is less toxic and a further decrease in concentration after mutagenic treatment minimizes its toxic effects. As these populations are growing in the same environmental and edaphic conditions, observed variability can be related to genetic makeup altered due to mutation. The RP-HPLC analysis results could form the basis of a more detailed study of root alkaloids and any marked similarity/dissimilarity in their alkaloid pattern may draw reasonable conclusions of the difference between the mutants and the parent cultivar.

Mutation breeding is an established method used for crop improvement and has played a major role in the development of many new flower color/shape mutant cultivars in ornamentals. The present study is aimed at inducing mutations in Delphinium malabaricum using chemical mutagens ethyl methane sulfonate (EMS), sodium azide (SA) and physical mutagen (gamma rays). It was observed that D. malabaricum manifested specific reactions to the treatments with EMS, SA and gamma rays. Identification and selection of mutations were carried out in the second generation (M2). A variety of chlorophyll deficient mutants and high percentage of the flower color and morphological mutants were recorded. The maximum frequency of chlorophyll and flower color and morphological mutations were recorded in EMS treated plants when compared to the other two mutagens. The frequency values for the individual mutant types were varied and randomly distributed at different mutagenic treatments. The highest percentage of color mutants arose after treatments with 0.25% of EMS and the lowest at 20 kR of gamma rays. The mutants were quite distinct, as compared to the control and often had more attractive ornamental features compared to the starting material. The major commercial benefit of the application of this technology has so far been obtaining of novel flower mutants that can be used as an initial material for further breeding of new cultivars.

Highly efficient in vitro regeneration system has been developed for Swertia lawii Burkill, an important herb used as substitute for Swertia chirayita. Shoot tips explants were cultured on MS medium with various phytohormones for multiple shoot production. The best shoot production frequency (100%) and maximum shoots (10.4 ± 0.8) were obtained on MS media containing TDZ (3.0 mg l−1) in combination with IBA (0.3 mg l−1). Maximum callus induction (95 ± 4.8%) and callus growth (1.7 ± 0.4 gm) was achieved on MS medium with 2, 4-D (3.0 mg l−1). Cell suspension cultures were established and studied for their growth kinetics. Shoots were rooted best (22.1 ± 2.5) in 1/2 MS medium with IAA (3.0 mg l−1). The genetic uniformity of the micropropagated clones was assessed using RAPD markers. Out of 405 bands, 400 (98.76%) were monomorphic and rest 5 (1.24%) were polymorphic. High multiplication frequency and low risk of genetic instability ensures the efficacy of this protocol.

Relation between 6-gingerol content and antioxidant activity in in vitro grown cultures of ginger was studied. Reverse phase HPLC analysis revealed that rhizome derived callus culture and micropropagated plants produced lowest amount of 6-gingerol compare to conventionally grown plants. The antioxidant activity of extracts was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and Ferric Reducing power assay (FRAP) and correlated with the content of total phenolics and total flavonoids in the extracts. Strong correlation was found between antioxidant activity, total phenolics and 6- gingerol content.

Swertia chirayita is one of the potential medicinal plants of the family Gentianaceae in traditional medicine. Due to its high demand and scarcity, trade of chirayita is affected by adulterants. Swertia species from Western Ghats were compared with S. chirayita for phytochemical characterisation and antioxidant activities by using different extracts. This study revealed that acetone is the best extraction solvent of phenolic and flavonoid compounds with antioxidant properties as compared with other extracts. S. chirayita showed better antioxidant activity than other species with highest content of phenolics and flavonoids. Among the species from Western Ghats, Swertia minor has better antioxidant properties with higher content of phenolics and flavonoids when compared with S. chirayita. Gallic acid was detected in all species under study by using HPLC analysis. The Swertia species under study showed similar phytochemical properties and antioxidant potential and hence their use as substitute to S. chirayita needs to be further investigated.

Rubia cordifolia L. is well known for its various medicinal properties. Its roots are the major source of its medicinally active ingredient Alizarin, an anticancer compound. For commercial extraction of useful compounds hairy root induction has been proven to be an efficient means of producing secondary metabolites that are normally biosynthesized in roots of differentiated plants. In present investigation standardization of a protocol for genetic transformation of R. cordifolia for hairy root induction and Chitosan as elicitor has been carried. The parameters viz. in-vitro grown leaf explants, Agrobacterium density (OD600 = 1.0) and incubation period (30 min) were optimized for hairy root induction (90%). Different concentrations of chitosan viz. 50, 100, 150 and 200 mg/l were tested to evaluate effect on accumulation of Alizarin in hairy root cultures. HPLC analysis was carried out for determining the period for maximum accumulation of Alizarin in hairy root cultures. The higher amount of Alizarin (4.65 ppm) in hairy roots elicited with 150 mg/l chitosan as compared to normal hairy roots (0.48 ppm) was observed on 15th day of inoculation. The results indicated that chitosan elicited 10 times higher accumulation of Alizarin in hairy root cultures. Thus the simple cost effective protocol has been reported for pharmaceutical use of Alizarin production via elicitation carried out in R. cordifolia. cultures.