Medicinal plants used for management of diabetes and hypertension in Ghana

**Background:** Diabetes and hypertension are declared global health menaces of the 21st century, with a high burden in developing countries where about 80% of the population relies on traditional medicine. In Ghana, diabetes prevalence is 4.1% and expected to rise to 5.0% by 2030, while hypertension affects about 46% of adults in Africa. The intensive management regimes, side effects, and high costs of orthodox drugs have driven a shift toward plant-based therapies. However, there is inadequate documentation of medicinal plants used by Ghanaian herbalists for these conditions. This study aimed to investigate the pharmacotherapeutic potential of medicinal plants used by herbalists in Ghana for managing diabetes and hypertension.

**Methods:** The study was conducted at the Centre for Plant Medicine Research (CPMR) in Akuapem-Mampong, Eastern Region, Ghana. A total of 36 registered herbalists (64% of 56 who attended a CPMR training workshop in September 2022) participated, representing Western (44%), Greater Accra (22%), Eastern (19%), and Ashanti (14%) regions. Ethnobotanical data were collected through semi-structured questionnaires, face-to-face interviews, and telephone conversations between September 2022 and January 2023. Voucher specimens were collected, pressed, and identified following standard ethnobotanical practices, with nomenclature verified using Plants of the World Online and The Plant List. Data were analyzed using Fidelity Level (FL) and Informant Consensus Factor (ICF).

**Key Results:** A total of 39 plant species from 31 families were reported. Of these, 18 species were used for hypertension alone, 12 for diabetes alone, and 9 for both diseases. The most common families were Apocynaceae and Fabaceae (14% each). Trees constituted 55% of plants used, shrubs 24%, and herbs 21%. The highest ICF was for plants used to treat both diseases (ICF=0.82), followed by hypertension (ICF=0.31) and diabetes (ICF=0.24). For hypertension, Tetrapleura tetraptera had the highest FL (15), followed by Persea americana and Launaea taraxacifolia (both 12.5). For diabetes, Momordica charantia had the highest FL (17.3), followed by Psidium guajava (13). For both diseases, Carica papaya had the highest FL (23.3). Three species—Baphia nitida, Luffa aegyptiaca, and Tapinanthus banguwensis—are reported for the first time in hypertension management. Herbalists diagnosed diabetes based on unexplained weight loss (36%), frequent urination (28%), increased thirst (25%), and extreme hunger (11%). Hypertension was diagnosed by irregular heartbeats (35%), difficulty breathing (22%), vision problems (16%), chest pains (14%), blood in urine (8%), and fatigue (5%). Most herbal medicines were prepared as decoctions from multiple plant parts, primarily leaves and stem bark, and administered orally. Literature review showed that 38 of the 39 plants have been investigated for biological activities (14 anti-diabetic, 16 anti-hypertensive, 8 for both), with bioactive compounds including alkaloids, terpenes, phenolics, and hydroxyl-containing compounds. However, clinical studies were few, with only Aframomum melegueta, Bryophyllum pinnatum, Cinnamomum zeylanicum, Momordica charantia, Rosmarinus officinalis, and Zingiber officinale having clinical evidence.

**Clinical Implications:** The study provides a comprehensive inventory of medicinal plants used by Ghanaian herbalists for diabetes and hypertension, with substantial preclinical evidence supporting their use. The high ICF for plants treating both diseases suggests shared therapeutic pathways, possibly through antioxidant, anti-inflammatory, or metabolic mechanisms. The identification of three novel species for hypertension warrants further pharmacological investigation. The predominant use of decoctions from multiple plant parts highlights the complexity of traditional formulations, which may enhance efficacy through synergism but poses challenges for standardization and quality control. The reliance on herbalists by a significant patient population (average 10 patients per week per herbalist) underscores the need for clinical trials to validate efficacy and safety, particularly for species like Carica papaya, Moringa oleifera, and Khaya senegalensis with high fidelity levels. Integrating validated herbal medicines into Ghana's healthcare system could improve access to affordable treatments, but rigorous clinical studies are essential to ensure patient safety and therapeutic reliability.