Medicinal Plants Classification Biosynthesis and ... - Index of

Management of Diabetes with Diet and Plant-Derived Drugs
compounds, uniflorines A and B, have been isolated from the leaves of Eugenia uniflora L.
and showed reduction in plasma glucose levels in sucrose tolerance tests on mice and
inhibited α-glucosidase enzyme (76).
Essential oils: A mixture of oleanolic acid and ursolic acid in a ratio of 2:1 isolated from
Phyllanthus amarus was screened for α-amylase inhibition and found to exhibit significant
inhibitory activity (77). Roselle tea extract is made from the dried flowers of Hibiscus
sabdariffa Linn. and is a popular beverage in Thailand. Hibiscus acid and its 6-methyl esters
isolated from a Roselle tea extract showed significant inhibition of porcine pancreatic
amylase (78). The essential oils from the wood of Juniper oxycedrus showed good activity
against α-amylase, while the wood and berries of the same plant possess significant
antioxidant activity (79). A diterpenoid, andrographolide isolated from an ethanolic extract of
Andrographis paniculata (Burm.f.) Nees (Acanthaceae) showed significant α-glucosidase
inhibition (80). Swietenine, a tetranortriterpenoid, isolated from Swietenia macrophylla seeds
showed significant in vivo hypoglycemic and hypolipidemic activity in Type II diabetic rats
(81).
Two new compounds, 7‘-(3‘, 4‘-dihydroxyphenyl)-N-((4-methoxyphenyl) ethyl)
propenamide and 7‘-(4‘-hydroxy, 3‘-methoxyphenyl)-N-((4-butylphenyl) ethyl)
propenamide, isolated from Cuscuta reflexa ROXB showed strong inhibition for αglucosidase
(82). Pipataline, pellitorine, sesamine, brachystamide B and guineensine were
isolated from Piper longum by bio-activity (α-glucosidase enzyme inhibition) guided
fractionation and found to possess potent inhibitory activity (83).
From the scientific evaluation of phyochemicals, it is clearly seen that the majority of
foods traditionally used to reduce hyperglycemia and related disorders (obesity etc) are rich
in polyphenolic compounds and flavonoids.
Conclusion
As α-amylase is a key enzyme for starch hydrolysis and α-glucosidase for intestinal
absorption, these enzymes help in digestion and uptake of carbohydrates. Inhibition of these
enzymes significantly decreases the postprandial increase of blood glucose level after a
mixed carbohydrate diet and can therefore be an important strategy in the management of
hyperglycemia linked to Type II diabetes. Currently available drugs, acarbose and voglibose,
which inhibit these enzymes, have associated side effects of abdominal distention, flatulence,
meteorism and diarrhea, which might be caused by the excessive inhibition of pancreatic αamylase
resulting in the abnormal bacterial fermentation of undigested carbohydrates in the
colon. Natural inhibitors from dietary sources have shown lower inhibitory effects against αamylase
activity and stronger inhibitory activity against α-glucosidase, which can be a good
strategy to reduce postprandial hyperglycemia with minimal side effects (24).
Lifestyle modifications and proper diet management are also important factors in the
treatment and prevention of diabetes mellitus and its related complications. Diabetes patients
should include wholegrain products, vegetables, fruits, low fat milk, food high in fibre, meat
products and other appropriate sources of proteins, soft margarines and vegetable oils rich in
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