How Longan Shell Extract Helps Prevent Apple Browning

Greg Howard
27th June, 2024

How Longan Shell Extract Helps Prevent Apple Browning

Image Source: Natural Science News, 2024

Key Findings

  • The study from Jiangxi Normal University found that longan shell tannins (LSTs) are effective inhibitors of the enzyme tyrosinase
  • LSTs can prevent the browning of fresh-cut apples, suggesting their use as natural preservatives in the food industry
  • LSTs may also help treat hyperpigmentation disorders and neurodegenerative diseases by inhibiting excessive tyrosinase activity
Tyrosinase is an enzyme that plays a crucial role in the browning of fruits and vegetables and the production of melanin in human skin. Excessive activity of this enzyme can lead to issues such as food spoilage and hyperpigmentation disorders in humans. The search for effective tyrosinase inhibitors has been ongoing, and a recent study from Jiangxi Normal University has identified longan shell tannins (LSTs) as promising candidates[1]. The study investigated the structure and inhibitory activity of LSTs, which were found to be mixtures of procyanidins (condensed tannins) and ellagitannins (hydrolyzed tannins). These compounds were shown to be effective inhibitors of tyrosinase, with IC50 values (a measure of inhibitor potency) of 176.04 ± 10 µg/mL for monophenolase and 59.94 ± 5 µg/mL for bisphenolase. This indicates that LSTs can efficiently inhibit the enzyme's activity at relatively low concentrations. The researchers used fluorescence detection and molecular docking techniques to explore how LSTs interact with tyrosinase. They discovered that the binding was primarily driven by hydrogen bonding, hydrophobic interactions, and van der Waals forces. These interactions altered the microenvironment of key amino acid residues (tyrosine and tryptophan) and changed the enzyme's conformation. Further analysis using circular dichroism and molecular dynamics simulations revealed that LSTs affected the secondary structure of tyrosinase, leading to structural stretching and conformational modifications. One of the significant applications of this study is in the food industry. The researchers demonstrated that LSTs could delay the browning of fresh-cut apples by inhibiting phenolic metabolism, strengthening the antioxidant system, and reducing lipid peroxidation. This finding suggests that LSTs could be used as natural preservatives to extend the shelf life of fresh produce. This study builds on previous research that has explored various tyrosinase inhibitors. For example, longan bark condensed tannins have also been identified as effective tyrosinase inhibitors, showing good inhibition of melanogenesis in mouse melanoma cells[2]. The current study extends these findings by focusing on longan shell tannins and their potential applications in both food preservation and medicine. The role of tyrosinase in human health is also noteworthy. Abnormal activity of human tyrosinase has been linked to hyperpigmentation disorders and neurodegenerative diseases such as Parkinson's disease (PD)[3][4]. Dysregulated tyrosinase activity can lead to the excessive production of melanin, contributing to skin disorders, and the loss of neuromelanin-positive neurons in the brain, which is associated with PD[4]. The identification of effective tyrosinase inhibitors, such as LSTs, could therefore have therapeutic implications beyond food preservation. In summary, the study from Jiangxi Normal University provides compelling evidence that longan shell tannins are potent tyrosinase inhibitors with potential applications in the food industry and medicine. By inhibiting tyrosinase activity, LSTs can prevent the browning of fruits and vegetables and may offer new avenues for treating hyperpigmentation disorders and neurodegenerative diseases. This research highlights the importance of natural compounds in developing safe and effective inhibitors for various applications.

FruitsBiochemPlant Science

References

Main Study

1) Inhibitory effect and molecular mechanism on tyrosinase and browning of fresh-cut apple by longan shell tannins.

Published 24th June, 2024

https://doi.org/10.1016/j.ijbiomac.2024.133326

Related Studies

2) Condensed Tannins from Longan Bark as Inhibitor of Tyrosinase: Structure, Activity, and Mechanism.

https://doi.org/10.1021/acs.jafc.7b05481

3) Heterocyclic Compounds as Synthetic Tyrosinase Inhibitors: Recent Advances.

https://doi.org/10.3390/ijms24109097

4) Dysregulation of tyrosinase activity: a potential link between skin disorders and neurodegeneration.

https://doi.org/10.1093/jpp/rgad107


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