Evaluation of the effect of insulin sensitivity-enhancing lifestyle- and dietary-related adjuncts on antidepressant treatment response: protocol for a systematic review and meta-analysis

Inhibitory potential of phenolic compounds of Thai colored rice (Oryza sativa L.) against α-glucosidase and α-amylase through in vitro and in silico studies

BACKGROUND

This study investigated the inhibitory efficiency of phenolic compounds content methyl vanillate, syringic acid and vanillic acid against α-glucosidase and α-amylase. The phenolic compound contents of 10 Thai colored rice cultivars were also determined, and the relationship between the inhibitory efficiency of colored rice extract with methyl vanillate, syringic acid and vanillic acid was evaluated.

RESULTS

The results revealed that the inhibition efficiency of methyl vanillate, syringic acid and vanillic acid was higher against α-glucosidase than against α-amylase. Inhibitory activity of vanillic acid against α-glucosidase and α-amylase was highest, with IC₅₀ of 0.100 ± 0.01 and 0.130 ± 0.02 mmol L^-1 , respectively. Docking study showed strong binding by three hydrogen bonds and four hydrogen bonds between vanillic acid with the amino acid in the binding site of α-glucosidase and α-amylase, respectively. Inhibition modes of these phenolic compounds were defined as a mixed type inhibition against α-glucosidase. Highest phenolic compound contents of methyl vanillate, syringic acid and vanillic acid were obtained from methanol extracts of all rice cultivars. The methanol extracts of all colored rice cultivars such as Khao Leum Pua also showed the highest inhibition potential against α-glucosidase and α-amylase. The results indicated that these phenolic compound contents were closely related to the inhibition potential of colored rice extracts against α-glucosidase and α-amylase.

CONCLUSION

Our results suggest that rice, especially colored rice cultivars, has the source of phenolic compounds. Moreover, the phenolic compounds had the greatest source of natural inhibitor against α-glucosidase and α-amylase. © 2022 Society of Chemical Industry.

Insulin Resistance and Blood-Brain Barrier Dysfunction Underlie Neuroprogression in Bipolar Disorder

Bipolar disorder (BD) often progresses to a more chronic and treatment resistant (neuroprogressive) course. Identifying which patients are at risk could allow for early intervention and prevention. Bipolar disorder is highly comorbid with metabolic disorders including type II diabetes mellitus (T2DM), hypertension, obesity, and dyslipidemia. Our studies have shown that insulin resistance (IR) is present in over 50% of patients with BD and that IR might underlie the progression of BD. While no confirmed predictors exist for identifying which patients with BD are likely to develop a more chronic course, emerging evidence including our own studies suggest that IR and related inflammatory pathways lead to impairments in blood-brain barrier (BBB) functioning. For the first time in living psychiatric patients, we have shown that the severity of BBB leakage is proportional to BD severity and is associated with IR. In this hypothesis paper we (i) highlight the evidence for a key role of IR in BD, (ii) show how IR in BD relates to shared inflammatory pathways, and (iii) hypothesize that these modulations result in BBB leakage and worse outcomes in BD. We further hypothesize that (iv) reversing IR through lifestyle changes or the actions of insulin sensitizing medications such as metformin, or optimizing BBB function using vascular protective drugs, such as losartan, could provide novel strategies for the prevention or treatment of neuroprogressive BD.

Combination effects of rice extract and five aromatic compounds against α-glucosidase, α-amylase and tyrosinase

Rice is a source of bioactive compounds related to human health and has been used for both consumption and traditional medicine. The authors investigated the synergistic and additive effect of rice extract (RE) combined with five aromatic compounds against three enzymes: α-glucosidase, α-amylase and tyrosinase. RE was purified by thin-layer chromatography (TLC) and preparative TLC (PTLC) with different solvent systems. RE had higher α-glucosidase and α-amylase inhibitory activity than the five aromatic compounds, while the five aromatic compounds had higher tyrosinase inhibitory activity than RE. The combination of RE/acarbose produced synergic inhibition of α-glucosidase and α-amylase, whereas RE showed additive inhibition of both enzymes when combined with aromatic compounds. The five aromatic compounds showed additive inhibition of tyrosinase when combined with RE. The combination of 2-methoxy-4-vinylphenol/vanillin/guaiacol produced synergistic inhibition of α-amylase while showing antagonism of α-glucosidase and tyrosinase. Interestingly, the RE produced additive inhibition of α-glucosidase, α-amylase and tyrosinase when combined with the 2-methoxy-4-vinylphenol/vanillin/guaiacol combination. RE had rich bioactive compounds related to α-glucosidase, α-amylase and tyrosinase inhibitory activity. Volatile compounds, including 2-methoxy-4-vinylphenol, vanillin and guaiacol, enhanced the inhibitory activity of RE against α-glucosidase, α-amylase and tyrosinase activities.

Evaluation of the effect of insulin sensitivity-enhancing lifestyle- and dietary-related adjuncts on antidepressant treatment response: A systematic review and meta-analysis

Background

Depression is associated with insulin resistance (IR). However, the potential beneficial effect, on antidepressant treatment response, of adjunctive therapy with insulin sensitivity-enhancing lifestyle and dietary interventions (exercise; supplementation with: vitamin D, magnesium, zinc, probiotics or omega-3 fatty acids) has not been systematically explored.

Aims

To determine the effect of the above stated adjuncts on antidepressant treatment response in clinically depressed patients via a systematic review and meta-analysis.

Methods

RCTs which assessed the effect, on antidepressant treatment response of adjunctive therapy with any of the interventions in comparison with treatment as usual were included.

Results

The interventions had a significant antidepressant effect, with SMD for follow-up (end of study) scores and change (from baseline) scores being -0.88, [95% CI: -1.19 to -0.57; P < 0.001] and -1.98 [95% CI -2.86 to -1.10; P < 0.001], respectively. The odds ratio (OR) for remission was 2.28 (95% CI 1.42 to 3.66; P < 0.001). The number-needed-to-treat (NNT) for remission was 6. Subgroup analysis of the follow-up scores revealed age effect: SMD significant in those with mean age ≤50 (-1.02 SMD; 95% CI: -1.40 to -0.64; p < 0.001) and insignificant in those with mean age >50 (-0.38 SMD (95% CI: -0.82 to 0.05; P = 0.08)). Also, the interventions were more beneficial among outpatients- SMD: -0.97 (95% CI: -1.32 to -0.62; P < 0.001) compared to inpatients- SMD: -0.34 (95% CI: -0.88 to 0.20; P = 0.22). Sensitivity analysis did not change the results.

Conclusion

The finding that antidepressant treatment response may be improved using insulin sensitivity-enhancing lifestyle and dietary adjuncts is worthy of further exploration.