Latest Research News on Alpha Amylase: Jan 2021

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Latest Research News on Alpha Amylase: Jan 2021

January 21, 2021 Biochemistry 0

Determinants of the diurnal course of salivary alpha-amylase

Objective

Previous data from our group and others have shown that salivary alpha-amylase activity increases in response to stress. It has been suggested that salivary alpha-amylase may be a marker for adrenergic activity. Less is known about other determinants of salivary alpha-amylase activation. The objective of the current study was to describe the diurnal pattern of salivary amylase and its determinants.

Methods

Saliva samples were collected immediately after waking-up, 30 and 60 min later, and each full hour between 0900 and 2000 h by 76 healthy volunteers (44 women, 32 men). Compliance was controlled by electronic monitors. In order to control factors which might influence the diurnal profile of salivary alpha-amylase (such as momentary stress, mood, food, or body activity), at each sampling time point the subjects filled out a diary examining the activities they had carried out during the previous hour.

Results

Salivary alpha-amylase activity shows a distinct diurnal profile pattern with a pronounced decrease within 60 min after awakening and a steady increase of activity during the course of the day. Mixed models showed a relative independence of diurnal salivary alpha-amylase from momentary stress and other factors, but significant associations with chronic stress and mood.

Conclusions

Our results suggest that diurnal profiles of salivary alpha-amylase are relatively robust against momentary influences and therefore may prove useful in the assessment of sympathetic nervous system activity. The findings underscore the need to control for time of day in studies using salivary alpha-amylase as a dependent variable. [1]

Human salivary alpha-amylase reactivity in a psychosocial stress paradigm

Biological indicators for stress reactions are valuable markers in psychophysiological research and clinical practice. Since the release of salivary enzyme alpha-amylase was reported to react to physiological and psychological stressors, we set out to investigate human salivary alpha-amylase changes employing a reliable laboratory stress protocol to investigate the reactivity of salivary alpha-amylase to a brief period of psychosocial stress.

In a within-subject repeated-measures design, 24 healthy adults were exposed to the TSST and a control condition on separate days with randomized sequence. Salivary alpha-amylase, salivary cortisol and heart rate were repeatedly measured before, during and after both conditions.

Significant differences between psychosocial stress and the rest condition in alpha-amylase activity [F(3.74,86.06)=4.52; P=0.003], cortisol levels [F(4.21,88.32)=12.48; P<0.001] and heart rate [F(1,22)=81.15; P<0.001] were observed, with marked increases before and after stress.

The data corroborate findings from other studies that showed increased levels of alpha-amylase before and after psychological stress. We discuss the role of salivary alpha-amylase as a promising candidate for a reliable, noninvasive marker of psychosocial stress. [2]

Stress-induced changes in human salivary alpha-amylase activity—associations with adrenergic activity

The salivary enzyme alpha-amylase has been proposed to indicate stress-reactive bodily changes. A previous study by the authors revealed marked increases in salivary alpha-amylase following psychosocial stress, indicating a stress-dependent activation of salivary alpha-amylase. Salivary alpha-amylase has been suggested to reflect catecholaminergic reactivity. Our aim was to assess/evaluate a possible relationship between salivary alpha-amylase and adrenergic parameters, i.e. catecholamines, as well as other stress markers.

Using an intra-individual repeated measures design, 30 healthy young men underwent the Trier Social Stress Test (TSST), which consists of a mental arithmetic task and free speech in front of an audience and a control condition in randomized order. Salivary alpha-amylase and salivary cortisol as well as plasma catecholamines and cardiovascular activity were repeatedly measured before, during, and after both conditions. [3]

Biotechnological Potential of Alpha Amylase Production by Bacillus subtilis Using Cassava Peel Powder as a Substrate

Cassava peels, a major agricultural waste associated with the processing of cassava tubers into value-added products such as industrial starch and derived food items including garri and foofoo, were used as raw material for the production of α-amylase. The major step of the process is solid state fermentation of the mash prepared from this by-product by Bacillus subtilis that was isolated from a solid municipal waste disposal site. The effects of varying durations of incubation, temperature, medium pH and substrate levels were characterized. The maximum α–amylase activity of 7.12 lU/ml/min was recorded in a medium containing 50g of dried cassava peel powder as substrate after 24 hours at a pH of 7.0 and temperature of 35°C. The crude α–amylase produced was confirmed by using it to hydrolyze industrial starch which yielded maltose, a demonstration that the enzyme produced can be used in different biotechnological processes. It can be concluded that the use of cassava peels as substrates for the production of α–amylase does not only add value and decrease the amount of this agro-industrial waste from the environment but also reduces the general cost of amylase production that is desired for various biotechnologically-based industrial applications. [4]

Alpha-amylase Inhibitory Compounds from Musa cavendishii

Aims: To investigate the ethyl acetate fraction from the methanol extract of the leaves of Musa cavendishii and to evaluate the alpha-amylase inhibitory activity of its isolated phytochemicals and their value as potential anti-obesity products.

Study Design: Isolation and identification of phytochemicals from the ethyl acetate fraction and investigation of their alpha-amylase inhibitory activity through In vitro screening and docking study.

Place and Duration of Study: Faculty of Pharmacy, Mansoura University, between June 2013 and July 2016.

Methodology: Different phytochemicals were isolated and purified using different chromatographic techniques from the ethyl acetate fraction of the extract of dried powdered leaves of Musa cavendishii. Elucidation of the structures of the isolated compounds was performed using different spectroscopic methods (1H NMR, 13C NMR, NOESY, HSQC and HMBC). Alpha-amylase inhibition assay was used to evaluate the inhibitory activity of the isolated compounds. Furthermore, docking study was conducted to get an insight about the binding mode of the active compounds within the active site of the target enzyme.

Results: (6S,9S)-roseoside 1-A was reported form the titled plant for the first time along with six reported compounds viz., (6S,9R)-roseoside 1-B, kaempferol-3-O-rutinoside 6, p-hydroxybenzoic acid 2, rutoside 7, catechuic acid 5, quercetin 4 and kaempferol 3. The diglucosides, kaempferol-3-O-rutinoside and rutoside exhibited better alpha-amylase inhibitory activity (80.45 and 98.0% inhibition, respectively) than the positive standard alph-amylase inhibitor (acarbose) used (57.0%) at a concentration of 50 µg/mL. In an agreement with the results of alpha-amylase inhibition assay, the docking results indicated that these two diglucosides 6 and 7, showed the highest binding scores (-8.16 and -7.68 kcal/mol) compared to positive standard acarbose (-5.40 kcal/mol).

Conclusion: This study showed that flavonoid diglucosides e.g. kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside (rutoside) could be potential inhibitors for alpha-amylase and could be used as anti-obesity phytochemicals. [5]

Reference

[1] Nater, U.M., Rohleder, N., Schlotz, W., Ehlert, U. and Kirschbaum, C., 2007. Determinants of the diurnal course of salivary alpha-amylase. Psychoneuroendocrinology, 32(4), pp.392-401.

[2] Nater, U.M., Rohleder, N., Gaab, J., Berger, S., Jud, A., Kirschbaum, C. and Ehlert, U., 2005. Human salivary alpha-amylase reactivity in a psychosocial stress paradigm. International Journal of Psychophysiology, 55(3), pp.333-342.

[3] Nater, U.M., La Marca, R., Florin, L., Moses, A., Langhans, W., Koller, M.M. and Ehlert, U., 2006. Stress-induced changes in human salivary alpha-amylase activity—associations with adrenergic activity. Psychoneuroendocrinology, 31(1), pp.49-58.

[4] Andi Brisibe, E. and Bankong, H. (2014) “Biotechnological Potential of Alpha Amylase Production by Bacillus subtilis Using Cassava Peel Powder as a Substrate”, Biotechnology Journal International, 4(11), pp. 1201-1211. doi: 10.9734/BBJ/2014/10856.

[5] Abdel-Raziq, M., Bar, F. and Gohar, A. (2016) “Alpha-amylase Inhibitory Compounds from Musa cavendishii”, Journal of Pharmaceutical Research International, 13(4), pp. 1-10. doi: 10.9734/BJPR/2016/29280.

 

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