Production of biomass and medicinal metabolites through adventitious roots in Ajuga bracteosa under different spectral lights.

Ajuga bracteosa an important medicinal herb, is getting endangered worldwide due to destructive harvesting by pharmaceutical industries in its different habitats. It is in dire need for protection and demands conservation and sustainable utilization. In the present study, effects of α-naphthalene acetic acid (NAA) under different spectral lights were estimated on the growth, secondary metabolism and biosynthesis of phenolic acids in adventitious roots (AR) cultures of A. bracteosa. Among the different spectral lights, highest AR induction frequency (88%) and formation of biomass (72 g/L FW and 22 g/L DW) were recorded in explants incubated in the presence of 1.5 mg/L NAA under yellow light. Maximum production of poly phenols (TPC;44.2 mg) and flavonoids (TFC;2.51 mg) were recorded in the AR cultures grown in the presence of blue light. Further, highest total protein content of (401.6 µg) was detected in the AR in response to normal white light. Blue spectral light induced maximum superoxide dismutase (SOD; 2.5 nM) and peroxidase activity (POD;0.85 nM) respectively, in AR cultures. Compared with other monochromatic lights, red light significantly enhanced the antioxidant potential of the AR cultures. Analysis through High performance liquid chromatography (HPLC-DAD) revealed significant variations in the levels of important phenolic acids such as gallic acid, catechin, rutin, caffeic acid, myricetin and apigenin in the AR samples treated with the lights of different spectra.

Micropropagation of Ajuga species: a mini review.

The genus Ajuga L., belonging to Lamiaceae family, is widespread. The demand for Ajuga species has risen sharply because of their medicinal, ornamental, and pharmacological properties. These wide-ranging plants are being rapidly depleted due to over-collection for ornamental and medicinal purposes, as well as by habitat destruction and deforestation. Ajuga boninsimae, A. bracteosa, A. ciliate, A. genevensis, A. incisa, A. makinoi, A. multiflora, A. pyramidalis, A. shikotanensis, A. reptans, and A. vestita are categorized and protected as endangered plants. In vitro plant culture has therefore emerged for the conservation and mass clonal propagation of rare plants. This mini-review covers the current in vitro scenario in the propagation of Ajuga species. Adventitious or axillary shoots are initiated on the leaf, petiole and internodes, as well as roots, nodes, and shoot tip explants. Shoot induction is predominantly dependent on plant growth regulators added to the culture medium. Full- or half-strength Murashige and Skoog medium with or without auxin is used for in vitro rooting. Rooted shoots need to be acclimatized in the greenhouse with an estimated 82-100% survival rate.

Seasonal and geographical impact on the morphology and 20-hydroxyecdysone content in different tissue types of wild Ajuga bracteosa Wall. ex Benth.

Ajuga bracteosa is an endangered medicinal herb which contains several natural products of therapeutic importance like 20-hydroxyecdysone (20-HE). As geography and habitat play a crucial role in the metabolism and morphology of a plant, the present study was aimed at evaluating the impact of phytogeography, season and tissue type on morphology and 20-HE content of A. bracteosa. The results revealed large morphological variations in various ecotypes of A. bracteosa. However, plants from the same altitude, regardless of their phytogeography, represented similar morphology. Effect of habitat on 20-HE content remained non-significant except for Karot (1608µg/g) and Kahuta (728µg/g). Effect of tissue types was significant (p value <0.016) for 20-HE content and followed ascending order: rootspring (1071µg/g)>summer (617µg/g). The aerial tissue types contained more 20-HE content in all seasons; especially during winter its amount radically rose in flowers (µ=2814µg/g). The aerial portion of Karot ecotype harvested in winter offers a valuable source of 20-HE. To confirm the effect of low temperature on 20-HE content, profiling of A. bracteosa raised in vitro at different temperature regime was carried out. On the basis of these results we hypothesize that chilling cold hampers vegetative growth and triggers stress induced 20-HE accumulation as a defense response.

Functional and phylogenetic diversity of root-associated bacteria of Ajuga bracteosa in Kangra valley.

Present study investigates the cultivable diversity of root-associated bacteria from a medicinal plant Ajuga bracteosa in the Kangra valley, in order to determine their plant growth promoting (PGP) and biotechnological potential. The plant was found to exhibit a positive rhizosphere effect of 1.3-1.5. A total of 123 morphologically different bacteria were isolated from the rhizospheric soil and roots of the plant. Medium composition was found to have significant effect on the composition of isolated bacterial populations. Majority of the rhizospheric soil isolates belonged to α- and γ-Proteobacteria, with Pseudomonas constituting the most dominant species. Endophytic bacterial community, on other hand, consisted almost exclusively of Firmicutes. Majority of the isolates showed PGP activity by producing siderophores and indole acetic acid. Several isolates were found to exhibit very high antioxidant activity in the culture medium. A significant proportion of isolates also demonstrated other ecologically important activities like phosphate solubilization, nitrogen fixation, and production of hydrolytic enzymes including amylase, protease, lipase, chitinase, cellulase, pectinase and phosphatase. Firmicutes were found to be metabolically the most versatile group and performed multiple enzyme activities. This is the first systematic study of culturable bacterial community from the rhizosphere of A. bracteosa, particularly in the Kangra valley region.