Synthesis and Antityrosinase Mechanism of Benzaldehyde Thiosemicarbazones: Novel Tyrosinase Inhibitors

Zhao

Food Bioprocess Technol

et al. 2017

In order to search for a new method for the antibrowning of food products, a novel hydroxypyridinone (HPO) derivative with a formyl group was evaluated for its anti-tyrosinase property. This compound was found to exhibit potent tyrosinase inhibition on the monophenolase activity of mushroom tyrosinase with an IC 50 value of 1.33 μM, indicating that this HPO derivative was 12-fold stronger than kojic acid (IC 50 15.89 μM). This molecule can inhibit tyrosinase via two action modes, namely copper reduction and chelation, and the formation of a Schiff's base with the amino group at the active site of the enzyme. A synergistic effect of these two action modes to enhance the inhibitory activity was observed. This compound was also investigated for the inhibitory effect on diphenolase activity of mushroom; the inhibitory mechanism was found to be reversible and of competitive-uncompetitive mixed-type inhibition. This hydroxypyridinone was demonstrated to effectively control the browning of vegetable products.

Section: Inhibition Mechanismsupporting

confidence: 91%

Section: Inhibitory Effect Of Compound 1 On Monophenolase Activity Ofsupporting

confidence: 67%

A Novel Inhibitor Against Mushroom Tyrosinase with a Double Action Mode and Its Application in Controlling the Browning of Potato

Zhao

Food Bioprocess Technol

et al. 2017

International Journal of Biological Macromolecules

“…Furthermore, we found that C-9 has two different inhibitory mechanisms within two concentration ranges. That was quite different from other tyrosinase inhibitors we previously studied [23][24][25]. We also found that C-9 had stronger bacteriostatic activity than previously identified compounds [26].…”

Section: Introductioncontrasting

confidence: 99%

Anti-tyrosinase kinetics and antibacterial process of caffeic acid N-nonyl ester in Chinese Olive (Canarium album) postharvest

Jia

Zheng

Feng

et al. 2016

Self Cite

Enzymatic browning and bacterial putrefaction are mainly responsible for quality losses of Chinese Olive (Canarium album) postharvest and lead to very short shelf life on average. Screening anti-browning and anti-bacterial agents is important for preservation of Chinese Olive. Caffeic acid N-nonyl ester (C-9) and caffeic acid N- Heptyl ester (C-7) was synthesized as inhibitors of tyrosinase, which is a key enzyme in browning process. The compound of C-9 could inhibit the activity of tyrosinase strongly and its IC50 value was determined to be 37.5μM, while the compound of C-7 had no inhibitory ability. Kinetic analyses showed that compound of C-9 has been a reversible inhibitory mechanism below 50μM and been irreversible mechanisms above 50μM. For the reversible inhibitory mechanism, the values of inhibitory constants (KI and KIS) were determined to be 24.6 and 37.4μM, respectively. The results of Chinese Olive fruit postharvest showed that the compound of C-9 could effectively anti-browning and anti-bacterial putrefaction. In addition, this compound had strong antibacterial activities against Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Salmonella. Therefore, C-9 could be a potential anti-browning and anti-bacterial reagent.

“…The characteristic maximum at 276.5 nm of compound oxygen of tyrosinase, which weakened the role of tyrosinase (Chen et al, 2012). Therefore, free radical scavenging compounds could also be used as a cosmetic ingredient to relieve skin aging (Tanaka et al, 2004).…”

Section: Methodsmentioning

confidence: 99%

Tyrosinase Inhibitory Effects and Antioxidant Properties of Paeonol and Its Analogues

Zhu

Cao

2013

FSTR

With the aim to find out structural features for the tyrosinase inhibitory activity, the inhibitory effects of seven paeonol analogues on the diphenolase of mushroom tyrosinase, the interaction between the inhibitors and the copper ions, and the antioxidant activity by DPPH radical were investigated. These paeonol analogues had suggested remarkable inhibition toward tyrosinase. Among them, paeonol (a) exhibited the strongest inhibition activity (IC 50 =0.21 mM) as well as showed potent scavenging activity on the DPPH radical. The inhibition kinetics revealed that paeonol (a) was a mixed-type inhibitor, 2′-hydroxy acetophenone (c), 4′-hydroxy acetophenone (d), and 2,4′-dihydroxy acetophenone (e) were competitive inhibitors, while acetophenone (b), 2′-methoxyacetophenone (f), and 4′-methoxy acetophenone (g) behaved as noncompetitive inhibitors. The maximum absorbing wavelengths of compounds (c), (d), and (e) showed different significant blue shifts, which could explain that they exhibited competitive inhibition by forming a chelate with the copper ions at the catalytic domain of the tyrosinase.Keywords: paeonol, acetophenone, tyrosinase inhibitor, DPPH radical, copper ions chelation *To whom correspondence should be addressed. E-mail: yuyanying@ncu.edu.cn IntroductionTyrosinase (EC 1.14.18.1), known as polyphenol oxidase, is a multifunctional copper-containing metalloenzyme widely distributed in nature. It mainly catalyzes the o-hydroxylation of monophenols to the corresponding catechols, and the oxidation of monophenols to the corresponding o-quinones (Yoon et al., 2009). Consequently, a series of high reactive quinones are produced to initiate the pigmentation and excessive activation of tyrosinase can cause various dermatological disorders, such as Parkinson and other degenerative diseases (Asanuma et al., 2003).One of the reactions catalyzed by the tyrosinase is the oxidation of L-dopa to L-dopaquinone by utilising molecular oxygen. In addition, reactive oxygen species (ROS) and free radical-mediated reactions are associated with various diseases, such as diabetes mellitus, cancer, ageing, skin disorders, and neurodegenerative diseases (Pham-Huy et al., 2008). If the inhibitors we have designed can weaken the tyrosinase activity as well as scavenge ROS effectively, the production of melanin and the damage of ROS to our human beings will be decreased to a great extent. Hence, tyrosinase inhibitors have become increasingly important in cosmetic (Guevara and Pandya, 2001) and medicinal (Kanost et al., 2004) industry, the food industry (Lunadei et al., 2011) and agriculture (Guerrero and Rosell, 2005) to prevent hyperpigmentation.In recent years, a large number of naturally occurring and synthetic tyrosinase inhibitors have been reported. There are many tyrosinase inhibitors, such as hydroquinone (Garcia and Fulton Jr, 1996), ascorbic acid (Kameyama et al., 1996), arbutin (Nakajima et al., 1998), kojic acid (Mishima et al., 1994, aromatic aldehydes (Jimenez et al., 2001;, aromatic acids (Chen et al., 2005;Si et a...