Impacts of elicitors on metabolite production and on antioxidant potential and tyrosinase inhibition in watercress microshoot cultures

The study has proved the stimulating effects of different strategies of treatments with elicitors on the production of glucosinolates (GSLs), flavonoids, polyphenols, saccharides, and photosynthetic pigments in watercress (Nasturtium officinale) microshoot cultures. The study also assessed antioxidant and anti-melanin activities. The following elicitors were tested: ethephon (ETH), methyl jasmonate (MeJA), sodium salicylate (NaSA), and yeast extract (YeE) and were added on day 10 of the growth period. Cultures not treated with the elicitor were used as control. The total GSL content estimations and UHPLC-DAD-MS/MS analyses showed that elicitation influenced the qualitative and quantitative profiles of GSLs. MeJA stimulated the production of gluconasturtiin (68.34 mg/100 g dried weight (DW)) and glucobrassicin (65.95 mg/100 g DW). The elicitation also increased flavonoid accumulation (max. 1131.33 mg/100 g DW, for 100 μM NaSA, collection after 24 h). The elicitors did not boost the total polyphenol content. NaSA at 100 μM increased the production of total chlorophyll a and b (5.7 times after 24 h of treatment), and 50 μM NaSA caused a 6.5 times higher production of carotenoids after 8 days of treatment. The antioxidant potential (assessed with the CUPRAC FRAP and DPPH assays) increased most after 24 h of treatment with 100 μM MeJA. The assessment of anti-melanin activities showed that the microshoot extracts were able to cause inhibition of tyrosinase (max. 27.84% for 1250 µg/mL). Key points • Elicitation stimulated of the metabolite production in N. officinale microshoots. • High production of pro-health glucosinolates and polyphenols was obtained. • N. officinale microshoots have got tyrosinase inhibition potential. • The antioxidant potential of N. officinale microshoots was evaluated. Graphical abstract

Uji Aktivitas Ekstrak Daun Dan Akar Singawalang (Petiveria alliaceae) Terhadap Penghambatan Tirosinase

Tyrosinase is an enzyme that plays a role in the formation of skin pigments from a person because it is involved in the process of melanogenesis. Tyrosinase plays a very important role in the skin depigmentation process, there are several attempts to inhibit the skin depigmentation process, one of which is by inhibiting tyrosinase. Research on the leaves and roots of singawalang (Petiveria alliacea) was conducted to determine the potential as a tyrosinase inhibitor. Leaves and root extracts of singawalang were macerated with ethanol, then tested for identification of secondary metabolites. Singawalang leaves extract contains alkaloids, tannins and terpenoids while singawalang root extract contains alkaloids, flavonoids, tannins and terpenoids. Tyrosinase inhibitory activity used the microplate reader ELISA technique at a wavelength of 492 nm. Tests were carried out on kojic acid as a comparison and L-DOPA as a substrate. The results of the tyrosinase inhibition activity test for the extracts of singawalang leaves, singawalang roots and kojic acid, IC50 were 9.817 mg / mL, 4.987 mg / mL and 0.092 mg / mL, respectively.

Design, Synthesis and Spectroscopic Characterizations of Medicinal Hydrazide Derivatives and Metal Complexes of Malonic Ester

Background: A new series of malonic acid-based hydrazide derivatives (BPMPDH, 2HPMPDH, 3HPMPDH, 4HPMPDH, DMPDH) are successfully synthesized by the reaction of malonic ester hydrazide with various substituted aldehydes like salicylaldehyde, benzaldehyde, 4-hydroxy benzaldehyde, 3-hydroxy benzaldehyde and formaldehyde) Methods: metal complexes of prepared hydrazide derivatives were prepared using metals like Cu+2, Zn+2 and Ni+2 via a mild, efficient and convenient method. Newly synthesized compounds were characterized by IR, NMR (1H & 13C), UV/VIS and mass spectrometry. The presence of –C=N- peak at 1600-1700 cm-1 with the absence of NH2 peak at 3500 cm-1 in FTIR spectra. In 1HNMR peak at, 11.00-13.00 ppm for –OH protons and 7.00-9.50 ppm for –NH verified the synthesis of new hydrazide derivatives. The presence of a C-OH sharp peak at 180-190 ppm, a C=O peak at 160-170 ppm and a C=N peak at 140-150 ppm confirmed synthesis. In mass spectra, the molecular ion peaks at 308 m/z, 340 m/z and 156 m/z confirmed synthesis. Synthesized compounds have also been analyzed for their antioxidant, antibacterial, antifungal, chymotrypsin and tyrosinase inhibition activities Result and Conclusion: The results revealed that the 2HPMPDH, 3HPMPDH, 4HPMPDH and their Cu+2 and Zn+2 metal complexes showed more successful inhibition against standard drugs, based on structure activity relationship.

Antioxidation and Tyrosinase Inhibitory Ability of Coffee Pulp Extract by Ethanol

Background. Following petroleum, coffee is the second most commonly traded commodity globally. It is also a popular good with economic value, as well as value in terms of leisure and culture. However, coffee processing generates a large amount of waste, resulting in environmental concerns. Therefore, in this study, ethanol was used to extract coffee waste (coffee pulp). High-performance liquid chromatography was conducted to examine the caffeine content and chlorogenic acid content, and the antioxidant capacity (i.e., the total phenolic content, total flavonoid content, DPPH-free radical scavenging capacity, ABTS-free radical scavenging capacity, and reductive capacity) and the tyrosinase inhibition capacity of the coffee pulp extracted using ethanol were comprehensively evaluated. Results. The results showed that the coffee pulp extract obtained using 70% ethanol had the highest tyrosinase inhibition capacity, whereas that obtained using 50% ethanol had the most satisfactory antioxidant capacity (total phenolic content, total flavonoid content, DPPH-free radical scavenging capacity, ABTS-free radical scavenging capacity, and reductive capacity). Conclusion. The results revealed that coffee pulp has superior antioxidant capacity and tyrosinase inhibition capacity when extracted by ethanol. Increasing the economic value of coffee pulp can solve the environmental concerns caused by coffee waste.

Application of Liposome Encapsulating Lactobacillus curvatus Extract in Cosmetic Emulsion Lotion

Probiotic extracts have various positive attributes, such as antioxidant, tyrosinase inhibitory, and antimicrobial activity. Lactobacillus curvatus produces bacteriocin, which activates the lipid membrane structure and has potential as a natural preservative for cosmetic emulsions. In this study, L. curvatus extract was encapsulated in liposomes and formulated as an oil-in-water (O/W) emulsion. Radical scavenging activity, tyrosinase inhibition, and challenge tests were conducted to confirm the liposome activity and the activity of the applied lotion emulsion. The liposome-encapsulated extract had a relatively high absolute ζ-potential (52.53 > 35.43), indicating its stability, and 96% permeability, which indicates its potential as an active agent in lotion emulsions. Characterization of emulsions containing the liposomes also indicated a stable state. The liposome-encapsulated extract exhibited a higher radical scavenging activity than samples without the extract and non-encapsulated samples, and the functionality was preserved in the lotion emulsion. The tyrosinase inhibition activity of the lotion emulsion with the liposome-encapsulated extract was similar to that of the non-treated extract. Candida albicans and Aspergillus niger were also inhibited in the challenge test with the lotion emulsions during storage. Collectively, these findings indicate that the liposome-encapsulated extract and the lotion containing the encapsulated extract have potential applicability as natural preservatives.

Determination of tyrosinase-cyanidin-3-O-glucoside and (−/+)-catechin binding modes reveal mechanistic differences in tyrosinase inhibition

Tyrosinase, exquisitely catalyzes the phenolic compounds into brown or black pigment, inhibition is used as a treatment for dermatological or neurodegenerative disorders. Natural products, such as cyanidin-3-O-glucoside and (−/+)-catechin, are considered safe and non-toxic food additives in tyrosinase inhibition but their ambiguous inhibitory mechanism against tyrosinase is still elusive. Thus, we presented the mechanistic insights into tyrosinase with cyanidin-3-O-glucoside and (−/+)-catechin using computational simulations and in vitro assessment. Initial molecular docking results predicted ideal docked poses (− 9.346 to − 5.795 kcal/mol) for tyrosinase with selected flavonoids. Furthermore, 100 ns molecular dynamics simulations and post-simulation analysis of docked poses established their stability and oxidation of flavonoids as substrate by tyrosinase. Particularly, metal chelation via catechol group linked with the free 3-OH group on the unconjugated dihydropyran heterocycle chain was elucidated to contribute to tyrosinase inhibition by (−/+)-catechin against cyanidin-3-O-glucoside. Also, predicted binding free energy using molecular mechanics/generalized Born surface area for each docked pose was consistent with in vitro enzyme inhibition for both mushroom and murine tyrosinases. Conclusively, (−/+)-catechin was observed for substantial tyrosinase inhibition and advocated for further investigation for drug development against tyrosinase-associated diseases.

Various Plants and Bioactive Constituents for Pigmentation Control: A Review

Hyperpigmentation disorders caused by excessive melanin synthesis may significantly affect the psychosocial aspect of an individual. Being the current gold standard used for the treatment of hyperpigmentation disorders, hydroquinone is associated with several adverse effects including skin irritation, contact dermatitis, mutagenic to mammalian cells, cytotoxic to melanocytes as well as exogenous ochronosis in darker-complexioned individuals. Botanically derived agents have received increased attention in treating hyperpigmentation as they are perceived to be milder, safer, healthier and more cost-effective. Several herbs, plant extracts and phytochemicals with multitude mechanisms of action have been reported to be effective depigmenting agents with milder side effects. Some of the agents were studied in combination and their hypopigmentation effects may be resulting from synergistic effects of the various components. Mechanisms involved in depigmentation include tyrosinase inhibition, inhibition of α-melanocyte-stimulating hormone-induced melanogenesis and antioxidant properties. Use of plant-derived agents for the treatment of hyperpigmentation disorders is promising with the need for more rigorous clinical studies to support the use of these agents. This review summarizes the use of various plants and bioactive constituents and their effectiveness in the control of pigmentation.