Background: The use of herbal therapies for treatment and management of diabetes mellitus
and complications associated with this chronic condition is increasing. Plants contain a bounty
of phytochemicals that have been proven to be protective by reducing the risk of various ailments
and diseases, including alkaloids. Moreover, alkaloids are known to be among the oldest natural
products used by humans for highlighting drugs that play crucial roles as therapeutic agents. The
reason for this expanding interest and uses of alkaloids as a part of plant natural compounds-based
treatments is that a significant proportion of diabetic patients do not respond very well to conventional
therapeutic medication. Furthermore, other explanations to this fact are the cost of medication,
side-effects, accessibility, and availability of health facilities and drugs and the inefficiency of these
medicines in certain cases.
Objective: In this study we aimed to review the literature on the valuable effects of herbs and
plants and their isolated alkaloids compounds as medication for management of diabetes, a prevalent
risk factor for several other disorders and illnesses.
Methods: In the current review, PubMed, ScienceDirect, Springer and google scholar databases
were used and the criterion for inclusion was based on the following keywords and phrases: diabetes,
hyperglycemia, complications of diabetes, alkaloids, antidiabetic alkaloids, hypoglycemic alkaloids,
alkaloids and complications of diabetes mellitus, mechanisms of action and alkaloids.
Results: In the current review, we demonstrate that alkaloids in the form of extracts and isolated
molecules obtained from a large variety of species demonstrated their efficiency for improving raises
in blood glucose either in animal models via experimental studies or in human subjects via clinical
trials. Medicinal species as chillies (Capsicum annuum), turmeric (Curcuma longa), barberry
(Berberis vulgaris) and cress (Lepidium sativum) are among the most common and therapeutic
plants used for controlling diabetes that were the subject of several experimental and clinical investigations.
Whereas, isolated alkaloids such as berberine, capsaicin and trigonelline have received
more interest in this field. Interestingly, the therapeutic impact of alkaloids against blood
glucose pathogenesis is mediated through a variety of signaling cascades and pathways, via inhibiting
or stimulating diversity of systems such as inhibition of α-glucosidase enzyme, blockade of PTP-
1B, deactivation of DPP-IV, increasing insulin sensitivity and modulating the oxidative stress.
Conclusion: Based on the findings of the present review, alkaloids could be used as preventive and
curative agents in the case of endocrine disorders, particularly diabetes and could play a promoting
function for the discovery of new antidiabetic agents.