Lo Han Kuo, a Low Glycemic Sweetner:Effects on Streptococcus mutans

Numerous zero/low-calorie artificial sweeteners currently available provide some level of health concerns in the general population or unique subsets of individuals (eg. phenylketonurics and diabetics).  Sugar alcohol sweeteners, ie. sorbitol, xylitol, marketed as noncariogenic sweeteners cause gastrointestinal disturbances in some individuals.  Thus, there appears a viable market for the identification of novel sweetening agents that can be: (1) used by the general population; (2) demonstrate anti-cariogenic capacity; (3) have a low glycemic index; and, (4) can be broadly used in foodstuffs.  Lo Han Kuo (LHK) extract is a novel zero-calorie high intensive natural sweetener, derived from the Chinese Lo Han Kuo fruit (Momordica grosvenori), is 300X sweeter than sucrose, and has recently been produced on an industrial scale. Objective: Critical research has not been conducted to examine biological parameters and potential health effects of LHK.  Methods: LHK extract (80%) and HPLC fractions were examined.  A resazurin-based microassay was screened for antimicrobial activity of LHK.  Growth on agar plates confirmed these bioactivities.  Effect of LHK extract on insulin production by pancreatic beta-cell cultures (mouse insulinoma cell line MIN6) was evaluated to examine glycemic activity of the sweetener.  Results: Our studies provide evidence that LHK extract has antibacterial activity against S. mutans compared with other major sweeteners.  HPLC results showed that LHK fraction #35 completely inhibits the growth of S. mutans.  This was extended to inhibitory capacity of these fractions for a range of oral/non-oral bacteria.  Finally, treatment of MIN6 cells with 1mM LHK extract stimulates insulin secretion by 2-fold, substantially greater than 1mM D-glucose.  Conclusions: LHK extract appears to inhibit the growth of S. mutans and minimized acid production by this species. Additionally, the LHK extract can function as a potent insulin secretagogue, which may be beneficial to patients with Type 2 diabetes who are using this zero-calorie natural sweetener.