The effect of 8 plant extracts and combinations on post-prandial blood glucose and insulin responses in healthy adults: a randomized controlled trial.

BACKGROUND: Lower post-prandial glucose (PPG) and insulin (PPI) responses to foods are associated with reduced diabetes risk and progression. Several plant extracts have been proposed to reduce PPG or PPI by inhibiting enzymes or transporters involved in carbohydrate digestion and uptake. This study evaluates a range of such extracts, consumed with a carbohydrate load, for their effects on PPG, PPI and indicators of (gastrointestinal) tolerance. METHODS: Interventions were extracts of mulberry fruit (MFE, 1.5 g), mulberry leaf (MLE, 1.0 g), white bean (WBE, 3.0 g), apple (AE, 2.0 g), elderberry (EE, 2.0 g), turmeric (TE, 0.18 g), AE + TE, and EE + TE. Each of these 8 individual extracts or combinations were added to a rice porridge containing ~ 50 g available carbohydrate (control). In a within-subject (randomised, balanced incomplete block) design, individual subjects received the control and a subset of 4 of the 8 extracts or combinations. Participants were 72 apparently healthy adults (mean [SD] age 31.2 [5.5] yr, body mass index 22.1 [2.0] kg/m2). The primary outcome was the percentage change in 2-h PPG (positive incremental area under the curve) relative to control. Secondary measures were the 2-h PPI response, 7-h breath hydrogen, measures of gastrointestinal discomfort, and urine glucose. RESULTS: In the 65 subjects who completed the control and at least one intervention treatment, additions of AE, MFE and MLE produced statistically significant reductions in PPG vs control (p < 0.05; mean effect - 24.1 to - 38.1%). All extracts and combinations except TE and WBE significantly reduced PPI (p < 0.01; mean effect - 17.3% to - 30.4%). Rises in breath hydrogen > 10 ppm were infrequent, but statistically more frequent than control only for MLE (p = 0.02). Scores for gastrointestinal discomfort were extremely low and not different from control for any treatment, and no glucosuria was observed. CONCLUSIONS: Additions of AE, MFE and MLE to rice robustly reduced PPG and PPI. EE significantly reduced only PPI, while TE and WBE showed no significant efficacy for PPG or PPI. Breath hydrogen responses to MLE suggest possible carbohydrate malabsorption at the dose used, but there were no explicit indications of intolerance to any of the extracts. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT04258501. Registered 6 February 2020 - Retrospectively registered.

Efficacy of fibre additions to flatbread flour mixes for reducing post-meal glucose and insulin responses in healthy Indian subjects.

The incidence of type 2 diabetes mellitus (T2DM) is increasing worldwide, including in developing countries, particularly in South Asia. Intakes of foods generating a high postprandial glucose (PPG) response have been positively associated with T2DM. As part of efforts to identify effective and feasible strategies to reduce the glycaemic impact of carbohydrate-rich staples, we previously found that addition of guar gum (GG) and chickpea flour (CPF) to wheat flour could significantly reduce the PPG response to flatbread products. On the basis of the results of an exploratory study with Caucasian subjects, we have now tested the effect of additions of specific combinations of CPF with low doses of GG to a flatbread flour mix for their impacts on PPG and postprandial insulin (PPI) responses in a South-Asian population. In a randomised, placebo-controlled full-cross-over design, fifty-six healthy Indian adults consumed flatbreads made with a commercial flatbread mix (100 % wheat flour) with no further additions (control) or incorporating 15 % CPF in combination with 2, 3 or 4 % GG. The flatbreads with CPF and 3 or 4 % GG significantly reduced PPG (both ≥15 % reduction in positive incremental AUC, P<0·01) and PPI (both ≥28 % reduction in total AUC, P<0·0001) compared with flatbreads made from control flour. These results confirm the efficacy and feasibility of the addition of CPF with GG to flatbread flour mixes to achieve significant reductions in both PPG and PPI in Indian subjects.

Brahmi for the better? New findings challenging cognition and anti-anxiety effects of Brahmi (Bacopa monniera) in healthy adults.

RATIONALE: A number of studies have indicated positive effects of long-term administration (3 months) of Bacopa monniera (Brahmi) on various cognitive functions especially memory and anxiety. However, inconsistent results in literature may be linked to various methodological issues. OBJECTIVE: The present study aimed to test the chronic effects (12 weeks) of 450 mg of a B. monniera (Brahmi) extract on learning and memory, information processing and anxiety in healthy adult Indian population. METHODS: The study design was a randomised, double-blind, placebo-controlled parallel design. Participants comprised of 72 healthy urban adults, both men and women, in the age range of 35-60 years who were educated and English speaking with basic knowledge of computers from Bangalore. The outcome measures included verbal learning and memory, inspection time, attention and interference. State and trait anxiety were additional outcome variables. RESULTS: In the present study, there were no significant differences between the two groups on any of the cognitive measures. However, there was a trend for lower state anxiety in the B. monniera (Brahmi) group as compared to placebo group. CONCLUSIONS: The current study attempted to determine the chronic effects of single daily dose of 450 mg of Brahmi extract on cognitive performance and anxiety in healthy adults. The results of the current study are not in agreement with findings of some of the earlier studies which have found improvement both on cognitive parameters and a reduction of anxiety scores.

DNA barcoding of authentic and substitute samples of herb of the family Asparagaceae and Asclepiadaceae based on the ITS2 region.

BACKGROUND: Herbal drugs used to treat illness according to Ayurveda are often misidentified or adulterated with similar plant materials. OBJECTIVE: To aid taxonomical identification, we used DNA barcoding to evaluate authentic and substitute samples of herb and phylogenetic relationship of four medicinal plants of family Asparagaceace and Asclepiadaceae. MATERIALS AND METHODS: DNA extracted from dry root samples of two authentic and two substitutes of four specimens belonging to four species were subjected to polymerase chain reaction (PCR) and DNA sequencing. Primers for nuclear DNA (nu ITS2) and plastid DNA (matK and rpoC1) were used for PCR and sequence analysis was performed by Clustal W. The intraspecific variation and interspecific divergence were calculated using MEGA V 4.0. STATISTICAL ANALYSIS: Kimura's two parameter model, neighbor joining and bootstrapping methods were used in this work. RESULTS: The result indicates the efficiency of amplification for ITS2 candidate DNA barcodes was 100% for four species tested. The average interspecific divergence is 0.12 and intraspecific variation was 0.232 in the case of two Asparagaceae species. In two Asclepiadaceae species, average interspecific divergence and intraspecific variation were 0.178 and 0.004 respectively. CONCLUSIONS: Our findings show that the ITS2 region can effectively discriminate Asparagus racemosus and Hemidesmus indicus from its substitute samples and hence can resolve species admixtures in raw samples. The ITS2 region may be used as one of the standard DNA barcodes to identify closely related species of family Asclepiadaceae but was noninformative for Asparagaceae species suggesting a need for the development of new markers for each family. More detailed studies involving more species and substitutes are warranted.