Plant still remain the most effective and cheapest alternative sources of drugs but due to civilization, little or no knowledge of the potency of some of these medicinal plants, humans have destroyed most of the plants which are within same proximity with them. The quality of DNA was assessed by spectrophotometry, gel electrophoresis, restriction endonuclease digestion and PCR amplification. A ratio of absorbance (A260/A280) in the range 1.8–2.0 indicates a high level of purity. The A260/A280 nm absorbance ratio ranged from 1.76–2.0 for T. triangulare and V. amygdalina for plant leaf mass in the range 0.1–0.4 g, indicating high purity of the isolated DNA. However, the yield decreased with increasing plant tissue amount per extraction buffer volume. The highest yields in T. triangulare and V. amygdalina (408.7 and 486.2 µg/g respectively) were obtained from a sample weight of 0.1 g per 500 µl of extraction buffer (Table 1). In the case of T. occidentalis, the optimum tissue amount for good quality and quantity genomic DNA was 0.2 g per 500 µl of extraction buffer (Table 1). Plant leaves amounts below and above the 0.2 g-threshold resulted in a reduction in spectral qualities. In conclusion, we have described a simple, safe, reliable, and cost-efficient CTAB DNA extraction method that provides high-quality DNA from recalcitrant water leaf, pumpkin leaf and bitter leaf in order to ascertain the quality control and scientific evidence for the efficacy and safety of medicinal plants. It was recommended that, for medicine to be safe and effective, the parameters that were mentioned must be considered. It is necessary to continue the development of patterns for the Nigeria Pharmacopoeia and of each country.