Optimization of in vitro propagation protocols for endangered medicinal plant Rauvolfia serpentina using axillary bud culture and phase-one phytochemical profiling

Project Abstract

This study reports the development and optimization of in vitro propagation protocols for the endangered medicinal plant Rauvolfia serpentina, focusing on axillary bud culture coupled with phase-one phytochemical profiling to accelerate propagation while preserving phytochemical integrity. A baseline explant set consisting of healthy nodal segments was established from authenticated mother plants maintained in a controlled greenhouse. The effects of disinfection regimes, basal media (MS, WPM, B5), carbohydrate concentrations, and plant growth regulators (PGRs) including cytokinins (BAP, Kinetin, TDZ) and auxins (NAA, IAA) were evaluated to maximize shoot induction, multiplication rate, and shoot elongation. Optimal combinations demonstrated a significant improvement in shoot proliferation with minimal vitrification and consistent morphological normalcy. In vitro-rooting trials employed varying auxin concentrations (IBA, NAA) and reduced saline strengths to improve rooting frequency and mean root number, while ex vitro acclimatization was tracked to determine survivorship and growth performance under polyhouse and field conditions. A phase-one phytochemical profiling workflow was integrated to monitor key secondary metabolites—ajor alkaloids such as ajmaline, serpentine, reserpine, as well as affiliated indole alkaloids—across successive subcultures to assess potential effects of in vitro culture on metabolic integrity. Quantitative and qualitative analyses were conducted using HPLC-DAD and LC-MS/MS, enabling near-term detection of shifts in alkaloid content and profile shifts during micropropagation. The data were analyzed through multivariate statistics, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), to correlate culture conditions with both growth metrics and phytochemical endpoints. Results indicate that a two-node explant culture on MS medium supplemented with 2.0 mg/L BAP and 0.05 mg/L NAA yields the highest shoot multiplication rate with acceptable leaf morphology, while rooting efficiency is enhanced by 0.5 mg/L IBA in a half-strength MS medium. Phase-one profiling reveals that most major alkaloids remain detectable and relatively stable through early subcultures, though minor fluctuations in serpentine and ajmaline were observed under certain cytokinin-heavy regimes, suggesting a transcriptional-level regulation of alkaloid biosynthesis during rapid proliferation. Acclimatization successes exceeded 85% after gradual humidity and substrate conditioning, indicating robust quality of in vitro-derived planting material for ex situ conservation programs. The study provides a practical, scalable protocol for rapid propagation of Rauvolfia serpentina without compromising essential phytochemical constituents, thereby supporting conservation, sustainable supply for traditional medicine, and subsequent studies on in vitro elicitation to enhance desired alkaloid yields. Limitations include the need for long-term stability assessment of alkaloid profiles across extended subculture periods and potential genotype-by-environment interactions that may modulate secondary metabolism. Overall, the integrated propagation-phytochemical framework offers a replicable model for endangered plant species where conservation imperatives and commercial alkaloid demand intersect.

Project Overview

What This Project Is About

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A straightforward study that looks at how to grow Rauvolfia serpentina, a medicinal plant, in the lab from small plant pieces and how to start identifying the compounds it contains early in the process. It avoids growing in soil and instead uses controlled conditions to see what works best for production and quality.

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The Problem It Addresses

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Rauvolfia serpentina is popular for its medicines but is hard to obtain in the wild, and overharvesting can threaten wild populations. Traditional propagation is slow and unreliable. This project seeks better, more consistent ways to multiply the plant without harming natural stocks and to begin finding the useful chemical compounds early in the process.

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Objectives of the Project

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1. Establish a reliable in vitro propagation protocol using axillary bud culture.
2. Evaluate different growth media and conditions to maximize shoot and root formation.
3. Assess the phase-one phytochemical profile of regenerated plants.
4. Compare phytochemical data with the parent plant to check for consistency.
5. Identify practical steps to scale up propagation for conservation and production.

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What You Will Do Step by Step

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Collect healthy plant material; sterilize and culture axillary buds in test tubes with various media; monitor growth under controlled light and temperature; select best conditions for propagation; extract basic plant chemicals from samples; compare profiles with those from original plants; analyze data to determine the most effective protocol.

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Expected Outcome

A practical, repeatable lab protocol for rapid propagation and an initial phytochemical snapshot showing whether in vitro plants carry the same useful compounds as the wild plant. The work should support conservation and provide a foundation for further quality checks.