Terminalin from African Mango (Irvingia gabonensis) Stimulates Glucose Uptake through Inhibition of Protein Tyrosine Phosphatases

Irvingia gabonensis baill. (African Mango): A comprehensive review of its ethnopharmacological significance, unveiling its long-standing history and therapeutic potential

ETHNOPHARMACOLOGICAL RELEVANCE

Irvingia gabonensis (Aubry-Lecomte ex O'Rorke) Baill. (IG) is a multipurpose tree native to tropical Africa such as Equatorial Guinea, Nigeria, Gabon, and Cameroon with high ethnomedicinal values.

AIM OF THE STUDY

This review emphasizes the ethnopharmacological significance, phytochemical, and functional properties of African mango, focusing on its potential for human health and industrial applications.

MATERIALS AND METHODS

Literature published on IG was traced by different databases, including the Egyptian Knowledge Bank database (EKB), ScienceDirect, PubMed, Google Scholars, Research Gate, Web of Science, Elsevier, and Scopus. Numerous keywords were used to achieve an inclusive search in the databases, like 'African Mango', 'Bush Mango', 'Irvingia gabonensis', 'Wild Mango', 'Dika Nut', 'Phytochemistry', 'Traditional uses', 'Functional foods', 'Polyphenols', 'Ogbono', 'Ellagic acid and its derivatives', and 'Pharmacological activities'.

RESULTS

Different parts of IG have been employed in traditional medicine and recorded a great success. The ripe fruit pulp was consumed fresh or processed into juice and wine documented for anti-diarrheal, anti-diabetic, anti-ulcer, hepatoprotective, antimicrobial, and anti-inflammatory properties. The kernels, which are widely traded and incorporated into traditional dishes, remain an integral part of culinary traditions. Seeds have folkloric uses for weight loss and are popular as blood thinners and anti-diabetics. Where the bark is reported for dysentery, colic, scabies, toothache, and various skin conditions. In Senegal, the stem bark is employed for gonorrhea, hepatic disorders, and gastrointestinal ailments. The leaves possess the potential to enhance renal and hepatic functions, safeguarding these vital organs against the detrimental effects of toxic substances. Pulp is rich in vitamin C, carbohydrates, and proteins. Oil is the major constituent of the seed, which is mainly composed of myristic and lauric acids. The defatted extracts are characterized by flavonoid glycosides and ellagic acid derivatives. Despite their widespread use, IG extracts are still inadequately characterized phytochemically and merit further investigation within the realm of scientific research. Encouragingly, toxicity studies have demonstrated the relative safety of IG extract at the administered doses.

CONCLUSION

The review extends our knowledge of the health benefits of IG, where these effects could be attributed to the phytochemicals present.

A mechanistic exploration of the metabolome of African mango seeds and its potential to alleviate cognitive impairment induced by high-fat/high-carbohydrate diets: Involvement of PI3K/AKT/GSK-3β/CREB, PERK/CHOP/Bcl-2, and AMPK/SIRT-1/mTOR Axes

ETHNOPHARMACOLOGICAL RELEVANCE

Irvingia gabonensis (Aubry-Lecomte ex O'Rorke) Baill., also known as "African mango" or "bush mango", belonging to family Irvingiaceae, has been mostly used as food and traditional medicine for weight loss and to enhance the health.

AIM OF THE STUDY

The overconsumption of high-fat and high-carbohydrate (HFHC) food induces oxidative stress, leading to neurological and cognitive dysfunction. Consequently, there is an immediate need for effective treatment. Hence, this study explored the efficacy of orlistat, metformin, and I. gabonensis seeds' total aqueous extract (IG SAE) in addressing HFHC-induced cognitive impairment by mitigating oxidative stress and their underlying mechanistic pathways.

MATERIALS AND METHODS

Initially, the secondary metabolite profile of IG SAE is determined using high-performance liquid chromatography coupled with a mass detector (UHPLC/MS). The in vivo study involves two phases: an established model phase with control (10 rats on a standard diet) and HFHC diet group (50 rats) for 3 months. In the study phase, HFHC is divided into 5 groups. The first subgroup receives HFHC diet only, while the remaining groups each receive HFHC diet with either Orlistat, metformin, or IG SAE at doses of 100 mg/kg and 200 mg/kg, respectively, for 28 days.

RESULTS

More than 150 phytoconstituents were characterized for the first holistic approach onto IG metabolome. Characterization of IG SAE revealed that tannins dominate metabolites in the plant. Total phenolics and flavonoids were estimated to standardize our extract (77.12 ± 7.09 μg Gallic acid equivalent/mg extract and 8.039 ± 0.53 μg Rutin equivalent/mg extract, respectively). Orlistat, metformin, and IG SAE successfully reduced the body weight, blood glucose level, lipid profile, oxidative stress and neurotransmitters levels leading to improved behavioral functions as well as histological alternation. Also, IG SAE halted inflammation, apoptosis, and endoplasmic reticulum stress, together with promoting autophagy, via modulation of PI3K/AKT/GSK-3β/CREB, PERK/CHOP/Bcl-2 and AMPK/SIRT-1/m-TOR pathways.

CONCLUSION

Metformin, orlistat, and IG SAE offer a promising multi-target therapy to mitigate HFHC diet-induced oxidative stress, addressing cognitive function. This involves diverse molecular mechanisms, particularly the modulation of inflammation, ER stress, and both PI3K/AKT/GSK-3β/CREB and AMPK/SIRT-1/m-TOR pathways. Furthermore, the higher dose of IG SAE demonstrated effects comparable to orlistat and metformin across most studied parameters.

Methyl Syringate Stimulates Glucose Uptake by Inhibiting Protein Tyrosine Phosphatases Relevant to Insulin Resistance

Several protein tyrosine phosphatases (PTPs), particularly PTPN1, PTPN2, PTPN6, PTPN9, PTPN11, PTPRS, and DUSP9, are involved in insulin resistance. Therefore, these PTPs could be promising targets for the treatment of type 2 diabetes. Our previous studies revealed that PTPN2 and PTPN6 are potential antidiabetic targets. Therefore, the identification of dual-targeting inhibitors of PTPN2 and PTPN6 could be a potential therapeutic strategy for the treatment or prevention of type 2 diabetes. In this study, we demonstrate that methyl syringate inhibits the catalytic activity of PTPN2 and PTPN6 in vitro, indicating that methyl syringate acts as a dual-targeting inhibitor of PTPN2 and PTPN6. Furthermore, methyl syringate treatment significantly increased glucose uptake in mature 3T3-L1 adipocytes. Additionally, methyl syringate markedly enhanced phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) in 3T3L1 adipocytes. Taken together, our results suggest that methyl syringate, a dual-targeting inhibitor of PTPN2 and PTPN6, is a promising therapeutic candidate for the treatment or prevention of type 2 diabetes.