Therapeutic Potential of Medicinal Plants and Their Phytoconstituents in Diabetes, Cancer, Infection, Cardiovascular Diseases, Inflammation and Gastrointestinal Disorders

1. Introduction

Conditions like diabetes mellitus (DM), cancer, infection, inflammation, cardiovascular diseases (CVDs) as well as gastrointestinal (GI) disorders continue to have a major impact on mortality and morbidity worldwide, and in the case of chronic illnesses - often associated with multiple complications - can severely impact quality of life [1,2,3]. Many of the modern synthetic medicines that are used to manage the aforementioned diseases present limitations that restrict their use. This includes being associated with adverse side effects, triggering drug-interactions and/or hypersensitivity reactions [4,5,6,7,8,9]. Additionally, a significant proportion of the world's population can neither afford nor easily access synthetic medicines [10].

Medicinal plants, generally considered safer, more affordable and accessible than synthetic medicines, have historically served as useful therapeutic agents in ethnomedicine. According to the World Health Organization (WHO), more than 80% of the world's population still relies on traditional medicine obtained from plants to meet their basic medical needs. Over the past few decades, there has been a surge in global interest for medicinal plants as an alternative to synthetic medicines. Unlike the latter, which are based on a single chemical entity, medicines based on plant extracts contain various phytoconstituents (e.g. flavonoids, alkaloids, polyphenols, terpenoids). Interestingly, these have been demonstrated to exert their pharmacological activities by interacting simultaneously with numerous biological targets, thereby increasing the therapeutic potential [1,2,11]. Moreover, the discovery that some phytoconstituents are able to enhance the bioactivity of others within a plant extract, an effect called synergism, is another great incentive for the use of medicinal plants [12,13].

The purpose of this review is to explore the most common medicinal plants used in ethnomedicine, their phytoconstituents, pharmacological properties and mechanisms of actions, for the management of DM, cancer, infection, inflammation, CVDs and gastrointestinal disorders. This article also discusses advancements in medicinal plants research and the future potential of medicinal plants in human health disorders.

2. Methodology

A comprehensive literature search was conducted using multiple databases including Google Scholar, Science Direct, Scopus and PubMed. During the search, the terms "Medicinal plants", "Ethnomedicine", "Herbal medicine", "Plant-based treatment", "Phytoconstituents", "Pharmacological action" and "The role of medicinal plants in the management of diabetes, cancer, infection, inflammation and gastrointestinal disorders" were used. Although the search approach was not limited to any particular time period, 98% of the articles obtained were published between 2000-2022 and only 2% predated the year 2000. Over 800 articles were shortlisted. Following a preliminary screening, approximately 400 articles were retrieved for in-depth analysis, and 105 of them were considered for our investigation. The important findings were compiled, analyzed, and presented in this review. The names of all plants were authenticated using the plant list (www.theplantlist.org) and the world flora (www.worldfloraonline.org).

3. Medicinal Plants in Traditional Systems of Medicines

The traditional knowledge/practice of using plants as medicines to cure and/or prevent disease among various ethnic communities is called ethnomedicine [14,15]. Medicinal plants have been used for centuries (mostly by those living in rural and/or remote communities) as part of traditional systems of medicines. These include Ayurveda, Unani, Traditional Chinese Medicine (TCM) and European Traditional Medicine [16,17,18].

Ayurveda is an ancient and widely popular medicinal practice, predominantly practiced in India but also frequently employed in other Southeast Asian countries (Bangladesh, Sri Lanka, Nepal, Pakistan) [19]. Over 20,000 medicinal plant species have been reported in India [20]. These include Acacia arabica (bark), Aframomum angustifolium (seeds), Allium sativum (leaves, cloves), Azadirachta indica (leaves), Curcuma longa (roots), Momordica charantia (fruits, leaves) (Table 1).

Unani traditional medicine was founded by Hippocrates (460–377 BC) and further developed by Arabian and Persian scientists in the Middle Ages, hence also called Greco-Arabian and Persian medicine [21]. Later introduced to India, it is now widely practiced in many Arabic and Asian countries and is a traditional medical practice recognised by the WHO [22]. Medicinal plants in Unani traditional medicine include Acacia arabica (bark), Allium sativum (roots), Azadirachta indica (leaves), Centella asiatica (leaves), Cinnamomum verum (leaves, bark), Curcuma longa (roots), Lantana camara (leaves), Musa paradisiaca (leaves, fruits), Trigonella-foenum graecum (leaves, seeds), Withania somnifera (roots), Zingiber officinale (roots) (Table 1) [23,24,25,26,27].

Traditional Chinese medicine (TCM) has long been employed to cure diseases in China, Japan, and other East and Southeast Asian countries with similar cultural traditions. TCM continues to be a significant part of the contemporary Chinese healthcare system, and it is becoming more well-recognized as a complementary and alternative medical practice worldwide [28]. Medicinal plants used in TCM include Aconitum heterophyllum (roots), Allium cepa L. (onion bulb), Allium sativum (leaves, cloves), Aloe barbadensis (leaves), Annona muricata (leaves, bark), Artocarpus heterophyllus (leaves, flowers, and fruits), Azadirachta indica (leaves, bark), Capsicum frutescens (leaves, fruits), Catharanthus roseus (leaves, root, and stem), Cinnamomum verum (leaves, bark), Citrus aurantium (leaves, fruits), Citrus limon (leaves, fruits), Curcuma longa (rhizome), Emblica officinalis (fruits), Eriobotrya japonica (leaves, seeds), Hibiscus rosa-sinensis (leaves, flowers, and roots), Momordica charantia (leaves, fruits, roots), Musa paradisiaca (leaves, peel), Ocimum sanctum (leaves, roots), Punica granatum (bark, fruits, and seeds), Withania somnifera (leaves, roots), Zingiber officinale (roots) (Table 1) [29,30].

Traditional European medicine has also a long history of use for the treatment of diseases and continues to be relevant in many European countries [31]. Popular traditional European medicinal plants include Acacia arabica (leaves, bark), Aframomum angustifolium (seeds), Aloe barbadensis (leaves), Allium sativum (leaves, cloves), Capsicum frutescens (leaves, fruits), Centella asiatica (leaves), Cinnamomum verum (leaves, bark), Citrus limon (fruits, peel), Curcuma longa (rhizome), Emblica officinalis (fruits), Eriobotrya japonica (leaves, seeds), Gymnema sylvestre (leaves), Momordica charantia (leaves, fruits, and roots), Musa paradisiaca (leaves, peel), Ocimum sanctum (leaves, stem, and roots), Pterocarpus marsupium (leaves, bark), Punica granatum (bark, fruits, and seeds), Zingiber officinale (root) (Table 1) [32,33,34].

4. Pharmacological Properties of Medicinal Plants

Medicinal plants traditionally used in ethnomedicine exhibit a wide range of pharmacological effects that have been demonstrated through scientific observation and testing [35,36]. These include antidiabetic, anticancer, antimicrobial, immunomodulatory, antioxidant, antihyperlipidemic, antihypertensive, cardioprotective, anti-inflammatory properties, as well as protective effects against GI disorders (Figure 1) [37,38,39]. The medicinal plants most commonly used in ethnomedicine for DM, cancer, infection, CVDs, inflammatory and GI disorders, along with their pharmacological actions are listed in Table 1.

4.1. Type 2 Diabetes Mellitus (T2DM)

Type 2 Diabetes mellitus refers to a group of metabolic conditions characterized by prolonged hyperglycemia due to impaired production, secretion or action of insulin [40]. Many medicinal plants and their bioactive phytoconstituents are used as traditional cures for type 2 diabetes have demonstrated ameliorating effects on high blood glucose level, restoring β-cell function, improving glucose tolerance, and glucose uptake, increasing insulin secretion, and insulin sensitivity, mitigating diabetes-induced ROS formation, possess free radical scavenging activity, inhibiting hydrolytic and oxidative enzymes, aldose reductase, and α-glucosidase effects [5,40,49,155,157]. Examples of plants with antidiabetic properties include Aframomum angustifolium (seeds), Curcuma longa (roots), Ocimum sanctum (leaves, roots), Terminalia chebula (fruit), Withania somnifera (roots) and Zingiber officinale (roots) (Table 1) [55,89,119,134,142,149].

4.2. Cancer

The use of medicinal plants in cancer therapy is considered an alternative approach to conventional treatment, and one that is potentially safer and better tolerated [41]. Many phytoconstituents possess anticancer or cancer chemoprotective properties, for example controlling oncogenesis expression, carcinogen metabolism, or inhibiting protein and DNA synthesis in cancer cells [42]. Many studies have demonstrated that medicinal plants can inhibit cancer cell generation by reducing the ameliorated expression of NF-κB and TNF-α, thus reducing tumor volume and weight, as well as tumor burden and incidence [137,144]. Plants with anticancer activity include Aloe barbadensis (leaves), Annona muricata (leaves, fruits), Artocarpus heterophyllus (fruits, leaves), Azadirachta indica (leaves, bark), Zingiber officinale (roots) (Table 1) [137,144].

4.3. Infectious Diseases

Infectious diseases are currently a severe global health concern [43]. Many medicinal plants exhibit antimicrobial or antiviral activity, inhibiting bacterial cell wall and protein synthesis, viral gene expression or viral entry into host cells [44,45]. As drug-resistant microbes become increasingly prevalent, research into antimicrobial medicinal plants has gained renewed importance [46,47]. Studies have revealed that medicinal plants can effectively reduce the growth of certain pathogens, such as Staphylococcus aureus, Salmonella typhimurium, Vibrio cholera, and Shigella dysenteriae [76,80]. Plants with notable antimicrobial activity include Aframomum angustifolium, Aloe barbadensis, Capsicum frutescens and Centella asiatica (Table 1) [76,80].

4.4. Cardiovascular Diseases

Cardiovascular diseases, the leading cause of death worldwide, can also be managed using medicinal plants [48]. Plant-based products have a long history of use in traditional medicine for treating CVDs [49]. Plant extracts have shown cardioprotective and anti-hypertensive activity by stimulating peroxisome proliferator-activated receptor γ (PPARγ) and suppressing calcium influx, respectively [42]. They can ameliorate triglyceride, total cholesterol (TC), LDL- and HDL-cholesterol as well as total protein levels effectively. They have also been reported to reinstate blood supply by prompting the proliferation of new blood vessels as well as lower blood pressure [48,49,50]. Plants with protective effects against CVDs include Acacia Arabica, Allium cepa, Azadirachta indica and Catharanthus roseus (Table 1) [54,59,60,74,77].

4.5. Inflammatory Diseases

Many current analgesics, such as opiates and non-steroidal anti-inflammatory drugs (NSAIDs), present adverse side effects [5,6]. The use of medicinal plants for the treatment of inflammatory conditions may lead to fewer side effects [51]. Medicinal plants and their bioactive phytoconstituents have been reported to possess anti-inflammatory activity by restoring free radical scavenging, inhibiting hydrolytic and oxidative enzymes, and reducing aldose reductase activity [40]. Several studies have shown that medicinal plants can reduce inflammation by inhibiting various inflammatory markers. These plants act by suppressing the activation of NF-κB, decreasing the expression of nitric oxide (NO) and inducible nitric oxide synthase (iNOS), inhibiting cyclooxygenase-2 (COX-2), and reducing tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) levels. Additionally, they can mitigate leukocyte adhesion and reduce the production of prostaglandin E2 [66,94,118]. Plants with anti-inflammatory effects include Aloe barbadensis Mill., Eriobotrya japonica and Ocimum sanctum (Table 1) [66,94,118].

4.6. Gastrointestinal Disorders

Plant-based medicines exert gastroprotective properties via mitigation of heartburn through inhibition of H⁺/K⁺-ATPase, alteration of GHR (ghrelin) sensitivity (which decreases hunger), increase in CCK and GLP-1 release, fasting leptin levels, gastric motility, suppression of abdominal pain causing L-type calcium channel, impediment of 5-HT3 receptors that lead to symptoms of dyspepsia, inhibiting α₂-adrenergic receptor, and regulation of mucus production [49]. Numerous medicinal plants are effective traditional remedies for GI disorders by reducing the ulcer index and gastric juice volume, increasing gastric juice pH and gastric wall mucus, reducing hyperemia and attenuating colon inflammation. Examples of plants with beneficial effects in GI disorders include Aloe barbadensis Mill. and Musa paradisiaca (Table 1) [66,114].

5. Phytoconstituents from Medicinal Plants and Their Therapeutic Mechanisms of Action

Medicinal plants contain numerous phytoconstituents, also referred to as phytochemicals, phytomolecules or bio-nutrients. These are organic substances that are synthesized naturally by plants to protect them against environmental challenges and attack from herbivores or microbial pathogens [44,155,156]. Phytoconstituents find commercial uses as biofuels, enzymes, preservatives, flavors, fragrances, and are found in numerous plant-based cosmeceutical and medicinal products. They can be extracted from different plant parts (e.g. roots, stem, leaves, flowers, seeds) using various extraction methods (Table 2) [157,158,159]. They belong to diverse classes of molecular structures, and many are biologically active. Their potential to interact with human biological targets is exploited for therapeutic purposes [18,44,155,156,160]. Indeed, many current drug classes (e.g. penicillins, opiates, taxanes, Vinca alkaloids and artemisinin derivatives) derive from bioactive phytoconstituents [36,161]. Unlike synthetic medicines, which use a single active ingredient to target a single biological target, medicinal plants display pleiotropic effects. This means that their numerous phytoconstituents are able to exert an overall effect by interacting with multiple targets/pathways [51].

5.1. Type 2 Diabetes Mellitus

T2DM is a chronic disease that significantly contributes to morbidity and mortality worldwide. It is often associated with complications like retinopathy, neuropathy, coronary heart disease, and stroke [162,163]. Notably, metformin, a widely used antidiabetic medication, is derived from the plant Galega officinalis and has been utilized for its therapeutic potential in enhancing insulin sensitivity [164]. Additionally, several other antidiabetic drugs are also derived from natural sources, highlighting the important role of plant-based compounds in the treatment of T2DM. Other phytoconstituents with antidiabetic activity include kaempferol, quercetin, catechin, allicin, alliin, diosgenin, L-leucine, marsupin, curcubitanes triterpenoids, azadiradione, gedunin and pterostilbene [5,43,52,58,71,191,213]. These compounds were observed to lower blood glucose levels through multiple mechanisms, including the reduction of α-glucosidase activity, enhancement of insulin sensitivity, and the elevation of intracellular calcium, which stimulates insulin secretion. [165,166].

For example, compounds cucurbitane triterpenoids activate GLUT4 translocation to the cell membrane, improves AMP-activated protein kinase activity, inhibits dipeptidyl peptidase IV (DPP-IV) activity, enhances glucose uptake and fatty acid oxidation, decreases triglyceride and low-density lipoprotein levels, increases high-density lipoprotein levels, reduces oxidative stress, heals pancreatic impairment, modifies pancreatic β-cells through increasing size, area, and numbers. Other examples of phytoconstituents with antidiabetic properties include diosgenin, which increases free radical scavenging/antioxidant activity, and limonoids azadiradione and gedunin, which inhibits α-amylase and α-glucosidase (Table 2) (Figure 2) [167,168].

5.2. Cancer

Cancer is a global disease that affects both urbanized and developing nations, with approximately 20 million individuals suffering from it as per 2022 data and this number is expected to rise to 35 million by 2050 [169]. Treatments based on plants have shown promising effects in the treatment of cancer [170], and phytoconstituents and their derivatives are promising treatment options for cancer patients, including as a means to attenuate the adverse side effects of anticancer drugs [171]. Examples of phytoconstituents with anticancer activity used for their therapeutic potential include vincristine and vinblastine obtained from Catharanthus roseus. These compounds are employed in the treatment of Hodgkin’s and non-Hodgkin’s lymphoma, choriocarcinoma, neuroblastoma, Wilkins’s tumor, reticulum cell sarcoma, leukemia in children, as well as neck and testicular cancer [18,157]. Other phytoconstituents with anticancer activity include allicin, aloesin, curcumin, capsaicin, diosgenin, β-sitosterol, brugine, vindoline and vindolicine [71,191,192,198,204]. The anticancer effects of capsaicin and curcumin have been demonstrated through various mechanistic pathways, which include inhibiting activator protein-1 (AP-1), PI3K/AKT/mTOR/AKT/FOXO, IGF-1R/p-Akt, Wnt-TCF, impeding HIF-1α/VEGF/Rho-GTPases via signal transducer and activator of transcription 3 (STAT3) signaling, declining PI3K/AKT/mTOR/AKT/FOXO pathway. Furthermore, Inhibiting IGF-1R/pAkt signaling transduction represses HER2-integrin, c-erbB-2, and MMP-2/9 by inhibiting protein kinase C (PKC) and mitogen-activated protein kinase (MAPK) signaling. It also inhibits nuclear factor kappa B (NF-κB) activation, arrests the cancer cell cycle at the G2 phase, and reduces oxidative stress (Table 2) (Figure 3) [172,173,174].

5.3. Infectious Diseases

The global threat of antimicrobial resistance (AMR) has led to an increased interest in discovering alternative treatment options to conventional antibiotics [175,176,177]. Several phytoconstituents have antimicrobial properties, and have shown promising potential against multi-drug resistant Gram-negative and Gram-positive bacteria [178]. Examples of phytoconstituents with antimicrobial activity include allicin, spirostanol azadirone, nimbin, gedunin, euxanthone, harunmadagascarin D, piperine, reserpine, berberine, chelerythrine, allitridin, quercetin, dictamnine, ellagic acid, gallic acid and aloe-emodin [71,191,192,196,207,219]. Compounds such as piperine, reserpine and berberine show their antimicrobial activity through the inhibition of efflux pumps, DNA intercalation or DNA gyrase inhibition. Dictamnine has been reported to inhibit topoisomerase IA, II and IV, inhibit bacterial cell division, cell wall formation, protein synthesis, replication, transcription and biofilm formation, slicing of intermediate complex of DNA topoisomerase I and, depolarize the bacterial cell membrane. Chelerythrine and allitridin are able to trigger bacterial cell lysis and suppress cell membrane Na+/K+-ATPase activity. Quercetin has been reported to interact with crucial enzymes such as β-lactamases while allicin can inhibit sulfhydryl dependent bacterial enzymes (Table 2) (Figure 4) [158,179,180].

5.4. Inflammatory Diseases

Chronic inflammation severely damages healthy tissues and has been associated with a variety of pathological conditions including cancer, neurological diseases and auto-immune disorders. Medicinal plants and their phytoconstituents can provide a valuable approach to prevent inflammatory processes [181]. Examples of phytoconstituents with anti-inflammatory potential include parthenolide, colchicine, capsaicin, kaempferol, resveratrol, naringenin. diosgenin, β sitosterol, quercetin, nimbidin, gallic acid, epicatechin, epigallocatechin, genistein, curcumin, catechin and plantamajoside. These exert their anti-inflammatory effect via multiple signaling pathways involved in inflammation [51,71,170,196,212]. Quercetin and catechin promote the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), γ-glutamylcysteine synthetase (γ-GCS) NADPH: quinone oxidoreductase-1 (NQO1) and the expression of heat shock proteins 70 (HSP70). Epigallocatechin suppresses lipoxygenase and cyclooxygenase. Curcumin inhibits inducible NOS (iNOS) and myeloperoxidase (MPO) activity. Quercetin suppresses M-CSF-activated macrophages, decreases IL-2 secretion, IL-2R expression, lysosomal enzyme release from activated neutrophils, PLA2 activity. Quercetin and curcumin inhibit IL-1β, IL-6, TNF-α, PGE2 production and NF-κB activation. Genistein suppresses tyrosine-protein kinase by inducing antiproliferative effects on T cells (Table 2) (Figure 5) [182,183].

5.5. Cardiovascular Diseases

Vascular dysfunction is a major contributor to the development of cardiovascular diseases (CVDs) and several scientific studies have emphasized the value of phytoconstituents in the prevention and treatment of cardiovascular disorders [184]. Phytoconstituents with protecting effects against CVDs include quercetin, curcumin, arjungenin, arjunic acid, arjunolic acid, ellagic acid, ginsenoside Rg1, ginsenoside Rg3 and luteolin [190,204,215,217,218]. Bioactive compound such as ginsenoside Rg1 is useful in preventing CVDs through various mechanisms including improving lipid profile by activating PPARα (peroxisome proliferator-activated receptor-alpha) levels, regulating the activation of the PI3K/Akt pathway, preventing acetylcholinesterase (ACE) activity and vascular smooth muscle cell (VSMCs) proliferation, decreasing adrenal catecholamine levels. Ginsenoside Rg3 has been reported to increase nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) levels, contributing to vasorelaxation and improved endothelial function. It activates Ca²⁺-gated potassium channels, which are crucial in modulating cellular excitability. Ginsenoside Rg3 also stimulates cholinergic pathways, activates M2 muscarinic receptors, and enhances the NO pathway, leading to vasodilation. Additionally, it reduces calcium overload and inhibits the Na⁺/Ca²⁺ exchanger, which is beneficial in myocardial ischemia. While specific studies on Rg3's effect on the phosphorylation of Akt/FoxO3a are limited, ginsenosides have been reported to influence the Akt signaling pathway, which is involved in cell survival and metabolism. Furthermore, Rg3 increases the phosphorylation of Nrf2, a key transcription factor, which upregulates antioxidant enzymes such as heme oxygenase-1 (HO-1), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione (GSH) content. These mechanisms collectively enhance the cellular antioxidant capacity and contribute to its therapeutic potential in cardiovascular and metabolic disorders. (Table 2) (Figure 6) [180,184].

5.6. Gastrointestinal Disorders

GI disorders are becoming more prevalent worldwide due to rapid globalization and lifestyle, primarily dietary habit, changes. Some GI disorders can be ameliorated with phytoconstituents [185]. Examples of phytoconstituents protecting against GI disorders include curcumin, amaroswerin, chebulagic acid, gallic acid, ternatin, tannins, quercitrin and chebulic acid [204,216,219]. Ternatin displays gastroprotective activity by suppressing intestinal transit, secretion and motility, hindrance of the cellular enzyme and neurotransmitter systems, interacting with calcium channels. Tannins have been reported to activate net water absorption, decrease electrolyte secretion, modify the activity of Na+K+ATPase, stimulate chloride channels, alter chloride secretion. Quercitrin can regulate arachidonic acid metabolism by suppressing COX and lipoxygenase activity, reduce Ca²⁺ availability during excitation-contraction coupling-related phases, excessive contractility of the ileum and jejunum, inhibit 5-HT3 receptors, antagonize the effect of 5-HT4 agonists, stimulate the PPARγ pathway, elevate acetylcholine levels by enhancing gastric motility and assisting gastric emptying, increasing the stomach and proximal small bowel motility and reduce pain by blocking muscarinic receptors (Table 2) (Figure 7) [186,187].

Phytoconstituents exhibit diverse therapeutic effects across various disease categories. These natural compounds exert multifaceted mechanisms of action, including the activation or inhibition of key signaling pathways, enzymes, and receptors. For example, in type 2 diabetes, phytoconstituents enhance glucose uptake and metabolic signaling while inhibiting enzymes linked to hyperglycemia. In cancer, they protect against oxidative stress and suppress pathways involved in tumor progression. In cardiovascular diseases, they modulate ion channels and signaling pathways to support cardiac health. Furthermore, phytoconstituents exhibit anti-inflammatory effects by reducing oxidative stress and cytokine activity, and combat infections by targeting microbial enzymes and proteins. Additionally, they alleviate gastrointestinal disorders by modulating enzymes and receptors linked to gut motility and inflammation. This broad-spectrum activity underscores their potential as natural therapeutic agents (Figure 8).

The phytoconstituents present in the medicinal plants most commonly used in ethnomedicine for DM, cancer, infection, CVDs, inflammatory and GI disorders, along with their pharmacological actions are listed in Table 2.

6. Concluding Remarks

Medicinal plants have long been recognized as important traditional medicines [228]. They have gained widespread popularity as alternative treatment option for diabetes mellitus, cancer, infection, cardiovascular diseases, inflammatory and gastrointestinal disorders [229,230]. In developing countries, medicinal plants are easily accessible, affordable, and often part of the diet [18,231,232]. They are also a rich source of bioactive phytoconstituents that can be used as templates for drug discovery. It has been estimated that around 25% of all currently available drugs derive from phytoconstituents [18,233,234]. In the early stages of drug discovery, the use of in-vitro and in-vivo experiments helps identify compounds that are safe, effective and with minimal adverse side effects [235]. The majority of the scientific studies evaluating the biological properties of medicinal plants investigated in this review have been conducted in-vitro and in-vivo. Further studies are warranted to fully investigate the clinical therapeutic benefits of the medicinal plants considered, and unravel the mechanisms of action of their bioactive phytoconstituents at the molecular level. Continued efforts to better understand the therapeutic potential of medicinal plants are required to alleviate the global burden of diseases.