Comparative Phytochemistry of Afromontane Forest and Lowland Rainforest Populations of Prunus africana in Nigeria

Prunus africana (African cherry) is a critically important medicinal tree exploited for its bark alkaloids used in prostate disorder treatment, and understanding phytochemical variation between afromontane and lowland rainforest populations in Nigeria has important implications for quality standardisation and conservation. This study compared the phytochemical profiles of Prunus africana bark from Mambilla Plateau afromontane populations (Taraba State) and the Obudu Plateau montane forest and Boshi Forest Reserve lowland populations (Cross River State). Bark samples from 10 individuals per population were collected, air-dried, powdered, and subjected to qualitative phytochemical screening and quantitative determination of total alkaloids, total flavonoids, total phenolics, and beta-sitosterol content. GC-MS analysis of methanol extracts was conducted to characterise the secondary metabolite fingerprints. One-way ANOVA and Tukey's post-hoc test were used to compare quantitative data. Qualitative screening confirmed alkaloids, flavonoids, tannins, and saponins in all populations, with minor differences in cardiac glycoside presence. Quantitative analysis revealed significantly higher total alkaloid content in Mambilla Plateau populations (mean: 4.82% dry weight) compared to Obudu (3.41%) and Boshi populations (3.09%, p < 0.01). Beta-sitosterol content was also significantly higher in montane populations. GC-MS identified 34 compounds in Mambilla extracts compared to 28 in Boshi extracts. Altitude and associated temperature and UV radiation differences were proposed as drivers of the alkaloid variation. The study recommends preferential harvesting protocols from higher-altitude populations for pharmaceutical sourcing, alongside urgent conservation measures for Mambilla populations. Keywords: Prunus africana, phytochemistry, afromontane, alkaloids, beta-sitosterol