Hello, there are a big number of substances with anti-diabetic activity.

Some substances names are attached.

Hope this info will help you.

In bee honeys the antimicrobial activity is due to the presence of phenolic acids and flavonoids. In the case of vegetable protein hydrolysates, the activity is attributed to the presence of medium and long chain peptides, which interact with cell membranes of microorganisms.

phenolic compounds are the majority compounds responsible for most of the plant extract activities. this review paper may help you

Our research have found that bioactive peptides from Phaseolus vulgaris L. have anti-diabetic potential. Please refer to these references:

https://onlinelibrary.wiley.com/doi/full/10.1002/jsfa.8053

Article Black bean peptides inhibit glucose uptake in Caco-2 adenoca...

Anthocyanins, a type of flavonoid, have been also involved in aminoration of insulin resistance:

https://onlinelibrary.wiley.com/doi/full/10.1002/mnfr.201700362

Thank you all for sharing your genuine scientific views regarding this topic.

The most potent compounds to reduce sugar are tannins, but there are plants that extract water or alcohol has the ability to affect the level of insulin, such as Anastatica Hierochuntica

@Raja k. Baker , If tannins are mostly responsible for the anti-diabetic activities, then polyphenols must be responsible for this activity.

Because tannins are also a class polyphenols. Isn't ??

The phenolic compounds and steviol glycosides present in the aqueous extracts of Stevia rebaudiana exhibit anti-diabetic activity by acting as inhibitors of amylolitic enzymes. The same metabolites have antioxidant and anti-inflammatory effects.

Not necessarily all phenolic compounds have the ability to reduce true sugar tannins are part of phenolic compounds and not all phenolic compounds tannins

@Rajaa k. Baker, okay.. Thank you so much for your opinion sharing..