Clinical Anti-Allergic Effects of African Vernonia amygdalina Leaf Extracts
Vernonia amygdalina Del. (VA) is an edible plant belonging to the Asteraceae family, genus Vernonia. This review mainly provides information about its effects on allergic skin disorders, namely, atopic and contact dermatitis. Leaf extracts of African V. amygdalina leaf contain several bioactive compounds, mainly flavonoids (luteolin, luteolin-7-O-glucuronide, luteolin 7-O-glucoside) and sesquiterpenes (vernodalin, vernodalol). It also contains a number of lipid and carbohydrates mainly threitol, inositol, hexadecanoic acid, and octadecanoic acid. After a personal experience on beneficial anti-inflammatory and anti-itch effects on skin disorders, we first conducted experimental studies using a mouse model of hapten-induced atopic dermatitis-like disease to evaluate the anti-itch and anti-allergic effects of VA leaf extracts. Later on, we conducted a preliminary comparative clinical trial in patients with atopic dermatitis (AD). In the prophylactic and curative studies in a mouse model of AD, V. amygdalina extracts (Vamex) displayed a better anti-itch effect than the steroid preparation (hydrocortisone), whereas it was as effective as hydrocortisone in regard to AD-like symptoms in mice. On the other hand, in a comparative preliminary clinical trial in African AD and CD patients, Vamex significantly reduced eczema area and severity index (EASI) and total serum immunoglobulin E (IgE) level as compared with Vaseline and was as effective as topical dexamethasone after a 2-week treatment period. Furthermore, our case reports on patients with complicated chronic and recalcitrant eczematous skin disorders also showed the beneficial effects of African V. amygdalina leaf-derived biomaterial on eczema, suggesting its potent anti-inflammatory and anti-allergic properties.
KeywordsAtopic dermatitis Contact dermatitis Pruritus Vernonia amygdalina
Eczema area and severity index
Extracellular signal-regulated kinases
Erythrocyte sedimentation rate
Gas chromatography-mass spectroscopy
Mitogen-activated protein kinases
We thank Professor Narufumi Suganuma and Professor Hidetoshi Sano from Kochi University Medical School from the Department of Environmental Medicine and Department of Dermatology, respectively; we also thank Dr. Takao Saruta from Saruta Dermatological Clinic and Dr. Maki Yokogawa from Yokogawa Dermatological Clinic in Kochi prefecture, Japan, for their wonderful support during the implementation of our environmental allergic skin disorders research, which consisted of our PhD thesis theme.
Conflict of Interest: Findings from our Vernonia amygdalina and skin allergy research have been subject to patent application in 2010; an international and a national (Japan) patents were obtained in 2012 and 2015, respectively.
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