Sirtuin 1 in osteoarthritis: Perspectives on regulating glucose metabolism.

Osteoarthritis (OA) is a degenerative disease characterised by articular cartilage destruction, and its complex aetiology contributes to suboptimal clinical treatment outcomes. A close association exists between glucose metabolism dysregulation and OA pathogenesis. Owing to the unique environment of low oxygen and glucose concentrations, chondrocytes rely heavily on their glycolytic capacity, exhibiting distinct spatiotemporal differences. However, under pathological stimulation, chondrocytes undergo excessive glycolytic activity while mitochondrial respiration and other branches of glucose metabolism are compromised. This metabolic change induces cartilage degeneration by reprogramming the inflammatory responses. Sirtuins, a highly conserved family of nicotinamide adenine dinucleotide (NAD+)-dependent deacetylases, regulate glucose metabolism in response to energy fluctuations in different cellular compartments，alleviating metabolic stress. SIRT1, the most extensively studied sirtuin, participates in maintaining glucose homeostasis in almost all key metabolic tissues. While actively contributing to the OA progression and displaying diverse biological effects in cartilage protection, SIRT1's role in regulating glucose metabolism in chondrocytes has not received sufficient attention. This review focuses on discussing the beneficial role of SIRT1 in OA progression from a metabolic regulation perspective based on elucidating the primary characteristics of chondrocyte glucose metabolism. We also summarise the potential mechanisms and therapeutic strategies targeting SIRT1 in chondrocytes to guide clinical practice and explore novel therapeutic directions.

Immunometabolism at the service of traditional Chinese medicine.

To enhance therapeutic efficacy and reduce adverse effects, ancient practitioners of traditional Chinese medicine (TCM) prescribe combinations of plant species/animal species and minerals designated "TCM formulae" developed based on TCM theory and clinical experience. TCM formulae have been shown to exert curative effects on complex diseases via immune regulation but the underlying mechanisms remain unknown at present. Considerable progress in the field of immunometabolism, referring to alterations in the intracellular metabolism of immune cells that regulate their function, has been made over the past decade. The core context of immunometabolism is regulation of the allocation of metabolic resources supporting host defense and survival, which provides a critical additional dimension and emerging insights into how the immune system and metabolism influence each other during disease progression. This review summarizes research findings on the significant association between the immune function and metabolic remodeling in health and disease as well as the therapeutic modulatory effects of TCM formulae on immunometabolism. Progressive elucidation of the immunometabolic mechanisms involved during the course of TCM treatment continues to aid in the identification of novel potential targets against pathogenicity. In this report, we have provided a comprehensive overview of the benefits of TCM based on regulation of immunometabolism that are potentially applicable for the treatment of modern diseases.

Deciphering nutritional interventions for podocyte structure and function.

Despite increasing awareness and therapeutic options chronic kidney disease (CKD) is still and important health problem and glomerular diseases constitute and important percentage of CKD. Proteinuria/albuminuria is not just a marker; but it also plays a direct pathogenic role in renal disease progression of CKD. Glomerular filtration barrier (GFB) which consists of fenestrated endothelial cells, fused basal membrane and interdigitating podocyte foot process and filtration slits between foot process is the major barrier for proteinuria/albuminuria. Many glomerular diseases are characterized by disruption of GFB podocytes, foot process and slit diaphragm. Many proteinuric diseases are non-specifically targeted by therapeutic agents such as steroids and calcineurin inhibitors with systemic side effects. Thus, there is unmet need for more efficient and less toxic therapeutic options to treat glomerular diseases. In recent years, modification of dietary intake, has been gained to treat pathologic processes introducing the concept of 'food as a medicine'. The effect of various nutritional products on podocyte function and structure is also trending, especially in recent years. In the current review, we summarized the effect of nutritional interventions on podocyte function and structure.

Nose to brain drug delivery - A promising strategy for active components from herbal medicine for treating cerebral ischemia reperfusion.

Cerebral ischemia reperfusion injury (CIRI), one of the major causes of death from stroke in the world, not only causes tremendous damage to human health, but also brings heavy economic burden to society. Current available treatments for CIRI, including mechanical therapies and drug therapies, are often accompanied by significant side-effects. Therefore, it is necessary to discovery new strategies for treating CIRI. Many studies have confirmed that the herbal medicine has the advantages of abundant resources, good curative effect and little side effects, which can be used as potential drug for treatment of CIRI through multiple targets. It's known that oral administration commonly has low bioavailability, and injection administration is inconvenient and unsafe. Many drugs can't delivery to brain through routine pathways due to the blood-brain-barrier (BBB). Interestingly, increasing evidences have suggested the nasal administration is a potential direct route to transport drug into brain avoiding the BBB and has the characteristics of high bioavailability for treating brain diseases. Therefore, intranasal administration can be treated as an alternative way to treat brain diseases. In the present review, effective methods to treat CIRI by using active ingredients derived from herbal medicine through nose to brain drug delivery (NBDD) are updated and discussed, and some related pharmacological mechanisms have also been emphasized. Our present study would be beneficial for the further drug development of natural agents from herbal medicines via NBDD.

Danhong injection in cardiovascular and cerebrovascular diseases: Pharmacological actions, molecular mechanisms, and therapeutic potential.

Cardiovascular and cerebrovascular diseases are the main cause of mortality worldwide, currently with less than optimum therapeutic options. Danhong injection (DHI) is a medicinal preparation based on two eminent Chinese herbal medicines, Salviae Miltiorrhizae (Dan Shen; family: Lamiaceae) and Flos Carthami (Hong Hua; family: Compositae/Asteraceae). DHI has been mainly used in the clinical therapy of cardiovascular (such as acute coronary syndrome and angina pectoris) and cerebrovascular diseases (such as stroke) in China for many years. The pharmacological properties of DHI include anti-inflammatory, anti-oxidant, anti-coagulatory, hypolipidemic, anti-apoptotic, vasodilatory, and angiogenesis-promoting actions. DHI offers a safe and effective therapeutic agent against cardiovascular and cerebrovascular diseases by modulating multiple disease-relevant signaling pathways and molecular targets. Herein, we provide a comprehensive review of the phytochemistry, therapeutic effects, molecular mechanisms, and adverse reactions of DHI in cardiovascular and cerebrovascular diseases. We also highlight the latest pharmacological advances and therapeutic potential of this promising herb-derived cardiovascular drug preparation.

Natural medicines for the treatment of fatigue: Bioactive components, pharmacology, and mechanisms.

It is a common phenomenon that people are in a sub-health condition and facing "unexplained fatigue", which seriously affects their health, work efficiency and quality of life. Meanwhile, fatigue is also a common symptom of many serious diseases such as HIV/AIDS, cancer, and schizophrenia. However, there are still no official recommendations for the treatment of various forms of fatigue. Some traditional natural medicines are often used as health care products, such as ginseng, Cordyceps militaris (L.ex Fr.Link) and Rhodiola rosea L., and these have been reported to have specific anti-fatigue effects with small toxic and side effects and rich pharmacological activities. It may be promising treatment strategy for sub-health. In this review, we first outline the generation of fatigue. Furthermore, we put emphasis on the anti-fatigue mechanism, bioactive components, and clinic trials of natural medicines, which will contribute to the development of potential anti-fatigue agents and open up novel treatments for sub-health.

Ferulic acid supresses Th2 immune response and prevents remodeling in ovalbumin-induced pulmonary allergy associated with inhibition of epithelial-derived cytokines.

Asthma is characterized by intermittent airway obstruction and chronic inflammation, orchestrated primarily by Th2 cytokines. There is a strong rationale for developing new asthma therapies, since current treatment protocols present side effects and may not be effective in cases of difficult-to-control asthma. The purpose of this study was to evaluate the effect of ferulic acid, a phenolic acid commonly present in plants, in the ovalbumin-induced pulmonary allergy murine model. METHODS: BALB/c mice were sensitized and challenged with ovalbumin, and treatments were provided by gavage. Six groups of mice (n = 6) were studied, labeled as: control, pulmonary allergy, dexamethasone, and 3 receiving ferulic acid (at 25, 50, and 100 mg/kg). Lung tissue, bronchoalveolar lavage fluid and serum were collected for analysis. RESULTS: Ferulic acid treatment inhibited an established allergic Th2-response by decreasing the key features of pulmonary allergy, including lung and airway inflammation, eosinophil infiltration, mucus production and serum levels of OVA-specific IgE. These results were associated with lower levels of CCL20, CCL11 and CCL5 chemokines and IL-4, IL-5, IL-13, TSLP, IL-25 and IL-33 cytokines in lung tissue homogenate. CONCLUSIONS: In this study it was demonstrated for the first time that ferulic acid treatment is able to suppress one of the main features of the airway remodeling, indicated by reduction of mucus production, besides the Th2 pathogenic response on ovalbumin-induced pulmonary allergy. Taken together, results shows that the immunopathological mechanism underlying these effects is linked to a reduction of the epithelial-derived chemokines and cytokines, suggesting that ferulic acid may be useful as a potential therapeutic agent for asthma.

How cyclodextrin encapsulation improves molecular stability of apple polyphenols phloretin, phlorizin, and ferulic acid: Atomistic insights through structural chemistry.

Phloretin (PRT), phlorizin (PRZ), and ferulic acid (FEA) prevalent in apples are unstable and less soluble in water, which can be improved by cyclodextrin (CD) encapsulation. This study aimed to provide atomistic insights of ß-CD-PRT (1), ß-CD-PRZ (2), and α-CD-FEA (3) complexes. Single-crystal X-ray diffraction (XRD) revealed that one PRZ (2) and one FEA (3) insert the aromatic B-ring and C=C-C=O(O) group respectively into the ß-CD (2) and α-CD (3) cavities, whereas a half-occupied PRT (1) inserts the B-ring across the ß-CD cavity. The induced-fit process yielded thermodynamically stable complexes 2 > 1 > 3, in agreement with the density functional theory (DFT)-optimized structures with the corresponding number of intermolecular OH···O H-bonds (7 > 3 > 1). Perpendicular conformations of the pharmaceutically active forms of PRT (1) and PRZ (2) are first observed crystallographically. This study confirmed the potential applications of CDs as molecular stabilizers and aqueous solubilizers for the improved bioavailability and efficient delivery of food bioactive compounds.

High yield production of cyanidin-derived pyranoanthocyanins using 4-vinylphenol and 4-vinylguaiacol as cofactors.

Pyranoanthocyanins are anthocyanin-derived pigments with vivid colors and enhanced stability, making them promising food colorants. We evaluated two 4-vinylphenols, decarboxylated p-coumaric (pCA) and ferulic acid (FA), as cofactors for pyranoanthocyanin formation. Cyanidin-3-glycosides from saponified black carrot were incubated with 4-vinylphenol or 4-vinylguaiacol in different anthocyanin-to-cofactor molar ratios (1:1-1:30) to form pyranoanthocyanins. Formation efficiency (45 °C, ≤96 h) was compared to their respective precursors at a 1:30 ratio. Composition changes were monitored using uHPLC-PDA-ESI-MS/MS. Pyranoanthocyanin yields with 4-vinylphenol (13.8-33.4%) were ∼12× higher than with pCA and yields with 4-vinylguaiacol (8.1-31.0%) were ∼6.5× higher than with FA. Molar ratios of 1:5 and 1:10 yielded significantly more pyranoanthocyanins. Pyranoanthocyanin formation with 4-vinylphenols followed first-order kinetics, whereas formation with hydroxycinnamic acids followed zero-order kinetics. Detection of intermediate compounds was consistent with a nucleophilic addition and aromatization formation mechanism. Overall, pyranoanthocyanin formation with 4-vinylphenols was more efficient than with hydroxycinnamic acids.

Enzymatic browning: The role of substrates in polyphenol oxidase mediated browning.

Enzymatic browning is a biological process that can have significant consequences for fresh produce, such as quality reduction in fruit and vegetables. It is primarily initiated by polyphenol oxidase (PPO) (EC 1.14.18.1 and EC 1.10.3.1) which catalyses the oxidation of phenolic compounds. It is thought that subsequent non-enzymatic reactions result in these compounds polymerising into dark pigments called melanins. Most work to date has investigated the kinetics of PPO with anti-browning techniques focussed on inhibition of the enzyme. However, there is substantially less knowledge on how the subsequent non-enzymatic reactions contribute to enzymatic browning. This review considers the current knowledge and recent advances in non-enzymatic reactions occurring after phenolic oxidation, in particular the role of non-PPO substrates. Enzymatic browning reaction models are compared, and a generalised redox cycling mechanism is proposed. The review identifies future areas for mechanistic research which may inform the development of new anti-browning processes.

Indoleamine 2,3 dioxygenase 1 immobilization on magnetic nanoparticles for screening inhibitors from coffee.

In this study, a ligand fishing method was developed to screen potential indoleamine 2,3-dioxygenase 1 (IDO1) inhibitors from coffee extracts by immobilization of IDO1 enzyme on amino-modified magnetic nanoparticles combined with UHPLC-Q-TOF-MS/MS analysis. Parameters including enzyme concentration, immobilization time, the pH of glutaraldehyde and the amount of magnetic nanoparticles were optimized. The results indicated that immobilized IDO1 could be reused 5 times and was stable during storage for 7 days. Several IDO1 ligands were captured by incubating immobilized IDO1 with coffee extract, of which 10 showed an obvious difference comparing to non-conjugated bare nanoparticles. In vitro inhibitory activity was further performed by CE analysis, in which ferulic acid and chlorogenic acid had better IDO1 inhibitory activity, with IC50 value of 113.7 µM and 307.5 µM. These results demonstrate that this method provides an effective platform for identifying and screening IDO1 inhibitors from natural products.

Insights into the effects of extractable phenolic compounds and Maillard reaction products on the antioxidant activity of roasted wheat flours with different maturities.

Experiments were performed to determine the effect of roasting whole wheat flours at 80 °C, 100 °C and 120 °C for 30 min on four forms of phenolics, Maillard reaction products (MRPs), and the DPPH scavenging activity (DSA) at 15, 30 and 45 days after flowering (15-DAF, 30-DAF, and 45-DAF). Roasting increased the phenolic content and antioxidant activity of the wheat flours, which were the dominant contributions to the formation of Maillard reaction products. The highest total phenolic content (TPC) and total phenolic DSA (TDSA) were determined in the DAF-15 flours at 120 °C/30 min. The DAF-15 flours exhibited the highest browning index and fluorescence of free intermediate compounds and advanced MRPs, suggesting that a substantial quantity of MRPs were formed. Four forms of phenolic compounds were detected with significantly different DSAs in the roasted wheat flours. The insoluble-bound phenolic compounds exhibited the highest DSA, followed by the glycosylated phenolic compounds.

Novel green production of natural-like vanilla extract from curcuminoids.

The demand for natural vanilla extract, and vanillin in particular, by far exceeds the current production, as both the cultivation of vanilla beans and the extraction of vanillin are laborious. For this purpose, most vanillin used today is produced synthetically, contrary to the general trend toward bio-based products. The present study deals with the synthesis of nature-based vanillin, starting with the more accessible rhizomes of the plant Curcuma longa. Besides vanillin, vanillic acid and p-hydroxybenzaldehyde are synthesized that way, which are also found in the natural vanilla bean. The extraction of the curcuminoids and, finally, their conversion to the flavors are performed using visible light and food-grade chemicals only. A binary mixture of ethanol and triacetin, as well as a surfactant-free microemulsion consisting of water, ethanol, and triacetin, are investigated in this context. The results exceed the literature values for Soxhlet extraction of vanilla beans by a factor > 7.

Changes in polyphenolic compounds and antioxidant activities of seed-used pumpkin during hydrothermal treatment.

An environmentally friendly physical processing method, hydrothermal treatment (HT), was used to increase the content of specific compounds and antioxidant activities of seed-used pumpkin byproducts. The influence of hydrothermal temperature (80 °C-160 °C) and time (30-150 min) on changes in polyphenols and antioxidation was evaluated. The results revealed that the maximum free polyphenol content (140 °C for 120 min) was 3.96-fold higher than the untreated samples. Elevated temperature and long duration changed phenolic acid contents. For example, p-coumaric acid, rutin and chlorogenic acid exhibited a decreasing trend, and p-hydroxybenzoic acid, quercetin and cinnamic acid showed an increasing trend. Compared to controls, HT was significantly associated with increased antioxidant activities. To comprehensively reveal the influence of hydrothermal temperature and time on changes in polyphenolic content, back propagation artificial neural network (BP-ANN) models with accurate prediction ability were developed, and the results exhibited well-fitted and strong approximation ability (R2 > 0.95 and RMSE < 2 %) and stability.

Membrane permeabilizers enhance biofortification of Brassica microgreens by interspecific transfer of metabolites from tea (Camellia sinensis).

Interspecific metabolite transfer (ISMT) is a novel approach for plants biofortification. In this study, the effect of tea (Camellia sinensis; Cs), with or without membrane permeabilizers EDTA and Tween, as a donor plant on broccoli, cauliflower and kale sprouts was investigated. As a result, caffeine- and catechin-enriched broccoli, cauliflower and kale microgreens were produced. Kale sprouts were most permeable for catechins from Cs, while cauliflower was most permeable for caffeine. Cs + EDTA significantly increased vitamin C in broccoli and kale. Among the tested enzymes activity, pancreatic lipase was the most affected by the treatment with broccoli and cauliflower biofortified with Cs or Cs combined with permeabilizers. Broccoli sprouts biofortified with Cs most significantly inhibited α-amylase, while those biofortified with Cs combined with permeabilizers most significantly inhibited α-glucosidase. Results point to ISMT combined with membrane permeabilizers as a promising and eco-friendly biofortification strategy to improve the biopotential of Brassica microgreens.

Ethnopharmacology of Rubus idaeus Linnaeus: A critical review on ethnobotany, processing methods, phytochemicals, pharmacology and quality control.

ETHNOPHARMACOLOGICAL RELEVANCE: Rubus idaeus Linnaeus (RI) is a Chinese herbal medicine that has been widely used in China for a long time to reinforce the kidney, nourish the liver, improve vision, and arrest polyuria. AIM OF THE STUDY: This work aims to evaluate the recent progress of the chemical composition, pharmacological activity, pharmacokinetics, metabolism, and quality control and of Rubus idaeus, which focuses on the insufficiency of existing research and will shed light on future studies of Rubus idaeus. METHODS: Literatures about "Rubus idaeus","Red raspberry" and "Fupenzi"are retrieved by browsing the database, such as Web of Science (http://www.webofknowledge.com/wos), Pubmed (https://pubmed.ncbi.nlm.nih.gov/), CNKI (http://www.cnki.net/), and Wanfang Data (http://www.wanfangdata.com.cn). In addition, related textbooks and digital documents are interrogated to provide a holistic and critical review of the topic. The period of the literature covered from 1981 to 2022. RESULTS: Approximately 194 compounds have been isolated from Rubus idaeus, which is rich in phenols, terpenoids, alkaloids, steroids, and fatty acids. Numerous investigations have demonstrated that Rubus idaeus exhibits many pharmacological activities, including hypoglycemic and hypolipidemic, anti-Alzheimer effect, anti-osteoporosis, hepatoprotective, anti-cancer, neuroprotective, anti-bacteria and skin care, etc. However, it is worth noting that most of the research is not associated with the conventional effect, such as reducing urination and treating opacity of the cornea. CONCLUSION: The effectiveness of Rubus idaeus has been proved by its long-term clinical application. The research on the pharmacological activity of Rubus idaeus has flourished. In many pharmacological experiments, only the high-dose group can achieve the corresponding efficacy, so the efficacy of Rubus idaeus needs to be further interrogated. Meanwhile, the relationship between pharmacological activity and specific compounds of Rubus idaeus has not been clarified yet. Last but not least, studies involving toxicology and pharmacokinetics are very limited. Knowledge of bioavailability and toxicological behavior of Rubus idaeus can help understand the herb's pharmacodynamic and safety profile.

A network pharmacology-based study on the quality control markers of antithrombotic herbs: Using Salvia miltiorrhiza - Ligusticum chuanxiong as an example.

ETHNOPHARMACOLOGICAL RELEVANCE: Salvia miltiorrhiza (Danshen, DS), the dried root and rhizome of Salvia miltiorrhiza Bunge and Ligusticum chuanxiong (Chuanxiong, CX), the dried rhizomes of Ligusticum striatum DC are effective in invigorating blood circulation and eliminating stasis which is highly related with cardiovascular disease (CVD). AIM OF STUDY: The identification of activity-based chemical markers is very important, but the complex mechanism of "multi-component, multi-target, and multi-effect" within traditional Chinese medicine (TCM) poses a great challenge to this work. In this study, we combined network pharmacological prediction with experimental validation of the DS and CX to explore an effective method for discovering quality control (QC) of antithrombotic herbs by clarifying the intermediate layer "module/cluster" between the whole complex system and a single component. MATERIALS AND METHODS: Based on structural similarity analysis of compound and the thrombosis network published before, we firstly modularized two layers called chemical cluster (CC) network and functional module (FM) network respectively and linked them into one bilayer modularized compound target (BMCT) network. "Two-step" calculation was applied on identifying the significant compounds as the potential QC markers from CC. The in vitro inhibitory activity of selected QC marker compounds on thrombin was evaluated to partially verify their pharmacological activities. HPLC was used to determine contents. RESULTS: According to the network-based analysis, nine compounds with great importance in the BMCT network were identified as QC markers of DS-CX, including tanshinone I, tanshinone IIA, cryptotanshinone, salvianolic acid B, ferulic acid, salvianolic acid A, rosmarinic acid, chlorogenic acid, and coniferyl ferulate. Enzyme inhibitory test partially verified the activity of tanshinone I and tanshinone IIA. Chemical profiling indicated that the nine marker compounds are the main components in the herbal pair. CONCLUSIONS: This study identified activity-based QC markers of DS-CX herbal pair and provided a new methodology that can be used in the QC of other herbs, herbal pairs, or formulas.

α-Glucosidase inhibitors from brown rice bound phenolics extracts (BRBPE): Identification and mechanism.

Brown rice bound phenolics extracts (BRBPE) have been reported to possess α-glucosidase inhibitory effects, the specific enzyme inhibitors involved in this process were unknown. Here, α-glucosidase inhibitors in BRBPE were screened using bioaffinity ultrafiltration methods, and seven phenolic compounds - three monomers (p-coumaric acid, ferulic acid and methyl ferulate), three dimers (8-5', 5-5' and 8-O-4' diferulic acid) and a trimer (5-5'/8-O-4″ dehydrotriferulic acid) were identified as exact inhibitors, among which 5-5'/8-O-4″ dehydrotriferulic acid and 5-5'diferulic acid exhibited the best inhibitory activity. Enzyme kinetic analysis suggested that the inhibitory mechanism of these seven inhibitors including competitive, noncompetitive, uncompetitive and mixed manner. Molecular docking analysis revealed that the seven inhibitors bind with α-glucosidase mainly by hydrogen bonding interaction, hydrophobic force and ionic bond. Molecular dynamics simulation further explored the structure and molecular property of phenolic-glucosidase complex. This work provided a deep insight into brown rice bound phenolics acting as potent α-glucosidase inhibitors.

Inhibition of the SARS-CoV-2 3CLpro main protease by plant polyphenols.

The abundance of polyphenols in edible plants makes them an important component of human nutrition. Considering the ongoing COVID-19 pandemic, a number of studies have investigated polyphenols as bioactive constituents. We applied in-silico molecular docking as well as molecular dynamics supported by in-vitro assays to determine the inhibitory potential of various plant polyphenols against an important SARS-CoV-2 therapeutic target, the protease 3CLpro. Of the polyphenols in initial in-vitro screening, quercetin, ellagic acid, curcumin, epigallocatechin gallate and resveratrol showed IC50 values of 11.8 µM to 23.4 µM. In-silico molecular dynamics simulations indicated stable interactions with the 3CLpro active site over 100 ns production runs. Moreover, surface plasmon resonance spectroscopy was used to measure the binding of polyphenols to 3CLpro in real time. Therefore, we provide evidence for inhibition of SARS-CoV-2 3CLpro by natural plant polyphenols, and suggest further research into the development of these novel 3CLpro inhibitors or biochemical probes.

Understanding the combined effect and inhibition mechanism of 4-hydroxycinnamic acid and ferulic acid as tyrosinase inhibitors.

The development of tyrosinase inhibitors to prevent the enzymatic browning have become a research hotspot in food industry. 4-Hydroxycinnamic acid (CA) and ferulic acid (FA) are both the derivates of cinnamic acids, which are widely coexisted in plants seeds and leaves. CA combined with FA (inhibition rate of 90.44%) were found to effectively inhibit tyrosinase activity than employing CA and FA alone (inhibition rate of 12.15% and 22.17%, respectively). CA-FA-tyrosinase complex resulted in fluorescence quenching. The first-order kinetics and Weibull models well described the inactivation of tyrosinase at 2-4 mM and 6-10 mM of CA and FA, respectively. Additionally, UV-vis spectrum indicated that several characteristic groups such as hydroxyl group in CA competed with the nucleophilic attack of intramolecular cyclization, leading to the decrease of characteristic peak. Molecular docking further studied that CA and FA interacted with the activity cavity of tyrosinase by amino acids residues Ser282, His263, and Val283.