In Vitro and In Vivo Inhibition of Skin Matrix Metalloproteinases by Pothomorphe umbellata Root Extract

Molecular basis of skin photoaging and therapeutic interventions by plant-derived natural product ingredients: A comprehensive review

Skin areas exposed to ultraviolet radiation (UV) from sunlight are more prone to photoaging than unexposed areas evidenced by several signs which include skin dryness, irregular pigmentation, lentigines, hyperpigmentation, wrinkling, and decreased elasticity. Plant-based natural product ingredients with therapeutic potential against skin photoaging are gaining more attention. This article aims the reviewing the research work done in exploring the cellular and molecular mechanisms involved in UV-induced skin photoaging, followed by summarizing the mechanistic insights involved in its therapeutics by natural product-based ingredients. In the mechanistic section of the convoluted procedure of photoaging, we described the effect of UV radiation (UVR) on different cellular macromolecules (direct damage) and subsequently, the deleterious consequences of UVR-generated reactive oxygen species (indirect damage) and signaling pathways activated or inhibited by UV induced ROS generation in various cellular pathologies of skin photoaging like inflammation, extracellular matrix degradation, apoptosis, mitochondrial dysfunction, and immune suppression. We also discussed the effect of UV radiation on the adipose tissue, and transient receptor potential cation channel V of photoaging skin. In the past few decades, mechanistic studies performed in this area have deciphered various therapeutic targets, opening avenues for different available therapeutic options against this pathological condition. So the remaining portion of the review deals with various natural product-based therapeutic agents available against skin photodamage.

Plant Secondary Metabolites against Skin Photodamage: Mexican Plants, a Potential Source of UV-Radiation Protectant Molecules

Human skin works as a barrier against the adverse effects of environmental agents, including ultraviolet radiation (UVR). Exposure to UVR is associated with a variety of harmful effects on the skin, and it is one of the most common health concerns. Solar UVR constitutes the major etiological factor in the development of cutaneous malignancy. However, more than 90% of skin cancer cases could be avoided with appropriate preventive measures such as regular sunscreen use. Plants, constantly irradiated by sunlight, are able to synthesize specialized molecules to fight against UVR damage. Phenolic compounds, alkaloids and carotenoids constitute the major plant secondary metabolism compounds with relevant UVR protection activities. Hence, plants are an important source of molecules used to avoid UVR damage, reduce photoaging and prevent skin cancers and related illnesses. Due to its significance, we reviewed the main plant secondary metabolites related to UVR protection and its reported mechanisms. In addition, we summarized the research in Mexican plants related to UV protection. We presented the most studied Mexican plants and the photoprotective molecules found in them. Additionally, we analyzed the studies conducted to elucidate the mechanism of photoprotection of those molecules and their potential use as ingredients in sunscreen formulas.

In vivo antitumoral effect of 4-nerolidylcatechol (4-NC) in NRAS-mutant human melanoma

NRAS-mutations arise in 15-20% of all melanomas and are associated with aggressive disease and poor prognosis. Besides, the treatment for NRAS-mutant melanoma are not very efficient and is currently limited to immune checkpoints inhibitors or aggressive chemotherapy. 4-nerolidylcathecol (4-NC), a natural product extracted from Pothomorphe umbellata, induces apoptosis in melanoma cells by ROS production, DNA damage and increased p53 expression, in addition to inhibiting invasion in reconstructed skin. Moreover, 4-NC showed cytotoxicity in BRAF/MEKi-resistant and naive melanoma cells by Endoplasmic Reticulum (ER) stress induction in vitro. We evaluated the in vivo efficacy and the systemic toxicity of 4-NC in a NRAS-mutant melanoma model. 4-NC was able to significantly suppress tumor growth 4-fold compared to controls. Cleaved PARP and p53 expression were increased indicating cell death. As a proof of concept, MMP-2 and MMP-14 gene expression were decreased, demonstrating a possible role of 4-NC in melanoma invasion inhibition. Toxicological analysis indicated minor changes in the liver and bone marrow, but this toxicity was very mild when compared to other proteasome inhibitors and ER stress inductors already described. Our data indicate that 4-NC can counteract melanoma growth in vivo with minor adverse effects, suggesting further investigation as a potential NRAS-mutant melanoma treatment.

ER stress promotes antitumor effects in BRAFi/MEKi resistant human melanoma induced by natural compound 4-nerolidylcathecol (4-NC)

Melanoma accounts for only 4% of malignant neoplasms of the skin, but is considered the most serious because it is highly deadly. Mutations in the MAPK (Ras-Raf-MEK-ERK) pathway is closely linked to the lack of control of cell proliferation. Especially in melanoma, this pathway has become a target for the development of oncogene-targeted therapies, such as the potent inhibitors of v-Raf murine sarcoma viral oncogene homolog B (BRAFi) and mitogen-activated protein kinase kinase (MEKi). Very high rates of response have been achieved, but most patients are relapsed due to the development of resistance, justifying the constant search for new therapeutic compounds. Early results from our group indicated that 4-nerolidylcatechol (4-NC), a catechol compound extracted from Pothomorphe umbellata, induces DNA damage, ROS production, increased p53 expression culminating in apoptosis in melanoma but with no data regarding the 4-NC effects in cells resistant to BRAFi or MEKi. Therefore, here we evaluated the role of 4-NC alone or in combination with BRAFi/MEKi in resistant melanoma cells. Double-resistant cells were generated and characterized by MAPK pathway reactivation. 4-NC alone or in combination (30 μM) with MAPK inhibitors was cytotoxic, inhibited colony formation and decreased invasiveness in two and three-dimensional cell culture models of treatment-naïve, BRAFi-resistant and BRAF/MEKi double-resistant melanoma cells. Apoptosis induction was demonstrated in resistant and double-resistant melanoma cell lines after 4-NC treatments. 4-NC showed important ability to induce apoptosis via Endoplasmatic Reticulum (ER) stress and specifically BiP and CHOP that had increased protein expression in all melanoma cell lines proving to be part of the ER stress pathway activation. CHOP knockdown slightly but enough increases cellular viability following 4-NC treatment indicating that apoptosis observed is partially dependent on CHOP. In summary, we show that 4-NC is a compound with activity against cutaneous melanoma, including resistant cells to clinically approved therapies.

Topical formulation containing Ilex Paraguariensis extract increases metalloproteinases and myeloperoxidase activities in mice exposed to UVB radiation

Ultraviolet B radiation represents 10% of the total UV radiation that reaches the Earth's surface, being the primary responsible for the biological effects related to skin cancer and photoaging. Ilex Paraguariensis A. St. Hil., known as Yerba mate (YM), is a native tree of South America whose polyphenols in its leaves are described to exhibit photochemoprotective effect and are employed in the treatment of cancer. Additionally, the polyphenols are used to prevent lipid peroxidation and reduce the UV-induced damage, which ultimately decreases the oxidative stress. Thus, the present study aimed to characterize a new YM extract, evaluate the extract cytotoxicity and develop a formulation containing YM extract to prevent UVB-induced damage in mice skin. The YM extract showed high levels of polyphenols, flavonoids, and tannins and exhibited excellent antioxidant activity. Its main components were suggested as chlorogenic acid (1.92%) and caffeic acid (0.41%). Besides, YM extract did not exhibit cytotoxicity in fibroblasts and decreased the activity of myeloperoxidase and metalloproteinase-2 after acute UVB exposure. As a result, the formulation containing the YM extract showed a potential photochemoprotective.

4-Nerolidylcatechol: apoptosis by mitochondrial mechanisms with reduction in cyclin D1 at G0/G1 stage of the chronic myelogenous K562 cell line

CONTEXT

4-Nerolidylcatechol (4-NRC) has showed antitumor potential through apoptosis. However, its apoptotic mechanisms are still unclear, especially in leukemic cells.

OBJECTIVES

To evaluate the cytotoxic potential of 4-NRC and its cell death pathways in p53-null K562 leukemic cells.

MATERIALS AND METHODS

Cytotoxicity of 4-NRC (4.17-534.5 μM) over 24 h of exposure was evaluated by MTT assay. 4-NRC-induced apoptosis in K562 cells was investigated by phosphatidylserine (PS) externalization, cell cycle, sub-G1, mitochondrial evaluation, cytochrome c, cyclin D1 and intracellular reactive oxygen species (ROS) levels, and caspase activity analysis.

RESULTS

IC50 values obtained were 11.40, 27.31, 15.93 and 15.70 μM for lymphocytes, K562, HL-60 and Jurkat cells, respectively. In K562 cells, 4-NRC (27 μM) promoted apoptosis as verified by cellular morphological changes, a significant increase in PS externalization and sub-G1 cells. Moreover, it significantly arrested the cells at the G0/G1 phase due to a reduction in cyclin D1 expression. These effects of 4-NRC also significantly promoted a reduction in mitochondrial activity and membrane depolarization, accumulation of cytosolic cytochrome c and ROS overproduction. Additionally, it triggered an increase in caspases -3/7, -8 and -9 activities. When the cells were pretreated with N-acetyl-l-cysteine ROS scavenger, 4-NRC-induced apoptosis was partially blocked, which suggests that it exerts cytotoxicity though not exclusively through ROS-mediated mechanisms.

DISCUSSION AND CONCLUSION

4-NRC has antileukemic properties, inducing apoptosis mediated by mitochondrial-dependent mechanisms with cyclin D1 inhibition. Given that emerging treatment concepts include novel combinations of well-known agents, 4-NRC could offer a promising alternative for chemotherapeutic combinations to maximize tumour suppression.

Physiological effect of olfactory stimuli inhalation in humans: an overview

The importance of odorants in human life has long been recognized. Literature contains different approaches of physiological and psychological effects of odorant compounds, fragrances and essential oils. This work discusses odorants inhalation effect, based on an overview of major studies in humans. Beneficial effect of fragrances is mainly related to human behaviour. Studies document odorants influence in sympathetic and parasympathetic nervous systems, and neurophysiological brain activity. Moreover, odours compounds can act on the neuroendocrine system, neurotransmitters and neuromodulators, influencing psychological behaviour as well as body function. Odorant inhalation modulates physiological pathways, and in some cases, results in skin function regulation. The mechanism is incompletely elucidated. These findings suggest that olfactory system plays a role in central nervous system function beyond that of smell. In this overview, it was observed that odour compounds influenced stress biomarkers, dehydroepiandrosterone, oxidative stress, estradiol, dopamine, cutaneous barrier, sebum secretion and cutaneous immune system in humans. Some can be related with skin function. As the skin is associated with an extensive biochemical cascade and has complex mechanisms, studies have far to go, as there are processes not yet investigated related to skin that may be affected through olfaction. Future researches are needed to further understand and describe the mechanisms of action of physiological effects in fragrance compounds.

Antioxidant effect of 4-nerolidylcatechol and α-tocopherol in erythrocyte ghost membranes and phospholipid bilayers

4-Nerolidylcatechol (4-NC) is found in Pothomorphe umbellata root extracts and is reported to have a topical protective effect against UVB radiation-induced skin damage, toxicity in melanoma cell lines, and antimalarial activity. We report a comparative study of the antioxidant activity of 4-NC and α-tocopherol against lipid peroxidation initiated by two free radical-generating systems: 2,2′-azobis(2-aminopropane) hydrochloride (AAPH) and FeSO₄/H₂O₂, in red blood cell ghost membranes and in egg phosphatidylcholine (PC) vesicles. Lipid peroxidation was monitored by membrane fluidity changes assessed by electron paramagnetic resonance spectroscopy of a spin-labeled lipid and by the formation of thiobarbituric acid-reactive substances. When lipoperoxidation was initiated by the hydroxyl radical in erythrocyte ghost membranes, both 4-NC and α-tocopherol acted in a very efficient manner. However, lower activities were observed when lipoperoxidation was initiated by the peroxyl radical; and, in this case, the protective effect of α-tocopherol was lower than that of 4-NC. In egg PC vesicles, malondialdehyde formation indicated that 4-NC was effective against lipoperoxidation initiated by both AAPH and FeSO₄/H₂O₂, whereas α-tocopherol was less efficient in protecting against lipoperoxidation by AAPH, and behaved as a pro-oxidant for FeSO₄/H₂O₂. The DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical assay indicated that two free radicals were scavenged per 4-NC molecule, and one free radical was scavenged per α-tocopherol molecule. These data provide new insights into the antioxidant capacity of 4-NC, which may have therapeutic applications for formulations designed to protect the skin from sunlight irradiation.

UV radiation-induced skin aging in hairless mice is effectively prevented by oral intake of sea buckthorn (Hippophae rhamnoides L.) fruit blend for 6 weeks through MMP suppression and increase of SOD activity

Oxidative stress and oxidative photodamage induced by UV radiation can cause serious skin damage that is characterized by wrinkling, roughness, laxity and pigmentation. The effects of a sea buckthorn (Hippophae rhamnoides L.) fruit blend (SFB) containing sea buckthorn fruit extract, blueberry extract and collagen on UV-induced skin aging were examined by treating hairless mice for 6 weeks with UV irradiation and SFB administered orally. The effects of SFB were measured in the skin of these mice by phenotypical and histological analysis and western blotting. According to wrinkle formation analysis, the oral intake of SFB induced a decrease in wrinkle formation in the damaged skin of UV-irradiated mice. The thickness of the epidermis and dermis in the vitamin extracts (Vit)- and SFB-treated group was lower than that in the vehicle-treated group, but the group treated with SFB50 was the most effective group. The mice treated with the Vit- or SFB solution maintained a normal moisture content through the inhibition of transdermal water loss (TEWL) and an increase in skin moisture content. Furthermore, the levels of matrix metalloproteinase (MMP) and collagen protein expression were assessed in five groups to examine the mechanisms underlying the effects of SFB oral intake. The application of SFB induced a decrease in MMP-1 and -9 expression to the levels observed in the vehicle-treated group, but MMP-9 expression showed a much larger decrease than MMP-1. Furthermore, the expression of collagen-1 in the skin corresponded to MMP expression except for the SFB30-treated group, whereas the superoxide dismutase (SOD) activity was increased dramatically in the SFB50-treated group. These results suggest that SFB has potential as a protective and therapeutic drug candidate against skin aging that functions by regulating the moisture content, MMP expression levels and SOD activity.

Morphological analysis of tissue reaction caused by a new endodontic paste in subcutaneous tissue of rats

Aim:

To assess the biocompatibility of an experimental endodontic paste based on the ethyl acetate fraction of Pothomorphe umbellata + calcium hydroxide, using propylene glycol as vehicle, in connective tissue of rats.

Materials and Methods:

Fifteen rats had four polyethylene tubes implanted in their backs, with each one containing the experimental paste. The tube side was considered the control group. After 7, 21, and 42 days, animals were euthanized.

Results:

Intense inflammatory reaction was noticed after 7 days for experimental paste and it was moderate for control group. At 21 days, the inflammatory reaction was moderate for experimental paste and discrete for control group; and at 42 days, it was discrete for experimental paste and control group. Statistical analysis (Dunn's test, P < 0.01) demonstrated significant difference between the fibrous capsule area at 7 and 42 days (P > 0.01) for experimental paste.

Conclusions:

Experimental endodontic paste presented satisfactory tissue reaction in the connective tissue of rats.

Impact of ultrasound-assisted extraction on quality and photostability of the Pothomorphe umbellata extracts

Pothomorphe umbellata (L.) Miq. is a Brazilian shrub with therapeutic and economic applications. There are some reports on the technological development of P. umbellata preparations; however, there are no studies on the influence of non-conventional extraction procedures on the quality of P. umbellata extracts. The aim of this study was to evaluate the effects of the ultrasound-assisted extraction (UE) parameters upon the extraction yield (EY%) of 4-nerolidylcatechol (4-NC) and the antioxidant activity of P. umbellata extracts using a factorial design and response surface methodology. Extracts obtained by UE and percolation were compared, and the photostability of 4-NC was evaluated via the exposure of UVA and visible light to the samples. The most influential variables observed for the UE were the ethanol-to-water and drug-to-solvent ratios. UE improved the extraction kinetics of 4-NC from plant material and improved the antioxidant activity of the extracts. Some of the ultrasound extracts showed an antioxidant activity that was not proportional to their 4-NC concentration, which suggests the presence of other active antioxidant compounds in these P. umbellata extracts. There was no significant difference in the photostability of 4-NC between the percolated and ultrasound extracts. Surprisingly, the isolated 4-NC material was significantly more stable when exposed to UVA-visible light compared to 4-NC in the plant extracts.

Inhibition effect of Gynura procumbens extract on UV-B-induced matrix-metalloproteinase expression in human dermal fibroblasts

ETHNOPHARMACOLOGICAL RELEVANCE

Gynura procumbens Merr. (Asteraceae) has been used as a traditional remedy for various skin diseases in certain areas of Southeast Asia.

AIM OF THE STUDY

In order to evaluate the protective activity of Gynura procumbens extract on skin photoaging and elucidate its mode of action.

MATERIALS AND METHODS

Matrix-metalloproteinase (MMP)-1 and -9 expressions were induced by UV-B irradiation in human primary dermal fibroblasts. MMP-1 expression level was measured by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Zymography was employed for evaluating the enzymatic activity of MMP-9. Anti-inflammatory activity and anti-oxidative capacity of the extract were evaluated by ELISA and dichlorodihydrofluorescein diacetate (DCF-DA) assay.

RESULTS

The ethanolic extract of Gynura procumbens inhibited MMP-1 expression up to 70% compare to negative control group. The enzymatic activity of MMP-9 was inhibited around 73% by the treatment of 20μg/mL of the extract. The extract markedly reduced the production of reactive oxygen species (ROS). Gynura procumbens extract showed an inhibitory effect on releasing pro-inflammatory cytokines (IL-6 and IL-8) in human HaCat keratinocyte.

CONCLUSION

The ethanolic extract of Gynura procumbens inhibited MMP-1 and MMP-9 expressions induced by UV-B irradiation via inhibition of pro-inflammatory cytokine mediator release and ROS production.

Piper umbellatum L.: a comparative cross-cultural analysis of its medicinal uses and an ethnopharmacological evaluation

AIM OF THE STUDY

This review assesses the botany, traditional medicinal uses, phytochemistry, pharmacology and toxicology of P. umbellatum.

MATERIALS AND METHODS

Information on P. umbellatum was gathered via the internet (using Scirus, Google Scholar, CAB-Abstracts, MedlinePlus, Embase, Scielo, and Web of Science) and libraries. Additionally, previously unpublished work on the traditional uses of P. umbellatum from our National Study of the Medicinal Plants of the Dominican Republic has been included.

RESULTS

Piper umbellatum is a Neotropical plant species widely distributed in Mexico, Central America, South America and the West Indian Islands. It has also been introduced to Africa and South-East Asia. Traditional uses for this plant are recorded in 24 countries in three continents, America, Africa and Asia for a wide range of ailments such as kidney, women diseases, diarrhea, skin affections, burns, rheumatism, malaria, intestinal parasites, inflammation and fever. We have analyzed the cross-cultural agreement among traditional uses in different countries and found a high degree of consensus for the indications kidney/diuretic, stomachache and wounds. Phytochemical studies of P. umbellatum have demonstrated the presence of terpenes (mainly found in the essential oil), alkaloids, flavonoids, sterols and other classes of secondary metabolites. The extracts and pure compounds derived from P. umbellatum show a wide spectrum of pharmacological activities including antibacterial, anti-inflammatory, analgesic, antioxidant, cytotoxic, antimalarial, antileishmanial, and antitrypanosomal activity. A first commercial product is in development, based on the plant's protective characteristics against UV irradiation.

CONCLUSIONS

The interesting biological activities of P. umbellatum need further research in in vivo experiments and clinical studies. The outcome of these investigations will determine the possible development of drugs from P. umbellatum.

Photoprotective effect of Pothomorphe umbellata on UVB radiation-induced biomarkers involved in carcinogenesis of hairless mouse epidermis

In this study we assessed the protective effect of topical application of Pothomorphe umbellata extract on ultraviolet B (UVB)-induced skin lesion parameters in hairless mouse epidermis. A single dose of UVB irradiation (0.23 kJ/m2) resulted in a significant decrease in thymine dimer-positive cells and apoptotic sunburn cells, with an increase in p53 and proliferating cell nuclear antigen-positive cells in the epidermis. After 5 weeks (total dose 13.17 kJ/m2) and 15 weeks (total dose 55.51 kJ/m2) of irradiation, P. umbellata treatment inhibited the hyperplasic response and induced an increase in p53-positive cells. These findings suggest that P. umbellata extract affords protection against UVB-induced skin lesions.

Plant extracellular matrix metalloproteinases

The plant extracellular matrix (ECM) includes a variety of proteins with critical roles in the regulation of plant growth, development, and responses to pests and pathogens. Several studies have shown that various ECM proteins undergo proteolytic modification. In mammals, the extracellular matrix metalloproteinases (MMPs) are known modifiers of the ECM, implicated in tissue architecture changes and the release of biologically active and/or signalling molecules. Although plant MMPs have been identified, little is known about their activity and function. Plant MMPs show structural similarity to mammalian MMPs, including the presence of an auto-regulatory cysteine switch domain and a zinc-binding catalytic domain. Plant MMPs are differentially expressed in cells and tissues during plant growth and development, as well as in response to several biotic and abiotic stresses. The few gene expression and mutant analyses to date indicate their involvement in plant growth, morphogenesis, senescence and adaptation and response to stress. In order to gain a further understanding of their function, an analysis and characterisation of MMP proteins, their activity and their substrates during plant growth and development are still required. This review describes plant MMP work to date, as well as the variety of genomic and proteomic methodologies available to characterise plant MMP activity, function and potential substrates.

Dose-dependent in vitro inhibition of rabbit corneal matrix metalloproteinases by an extract of Pothomorphe umbellata after alkali injury

The in vitro ability of Pothomorphe umbellata ethanolic crude extract to inhibit matrix metalloproteinase (MMP) in normal cornea and in cornea after alkali injury was demonstrated. Corneas of albino rabbits were injured with 1 N NaOH for 20 s. After 48 h the corneas were excised, homogenized and analyzed for MMP-9 (92 kDa), pro-MMP-2 (72 kDa) and MMP-2 (67 kDa) activity by gelatin zymography. The activity was also measured in untreated corneas. After electrophoresis of 20 microg protein, gels were incubated with 50, 100, or 250 microg/mL lyophilized hydroethanolic (1:1) root crude extract of P. umbellata standardized for 4-nerolidylcatechol (7.09%). The activity of the enzymes was compared with that of untreated gel. At 48 h after injury, the activity of all MMPs was increased compared with untreated eyes. When the gels were incubated with P. umbellata extract the activity of MMP-2, pro-MMP-2 and MMP-9 decreased in a dose-dependent manner. MMP-9 activity decreased by approximately 50% after incubation with 50 microg/mL and was completely abolished at 100 and 250 microg/mL of the extract. After incubation with 50 microg/mL the activity of pro-MMP-2 and MMP-2 also decreased by 50%. The activity of pro-MMP-2 was almost completely abolished after incubation with 250 microg/mL of the extract. For MMP-2 the incubation with 100 or 250 microg/mL of the extract of P. umbellata promoted a 10-fold decrease in activity. In conclusion, P. umbellata root crude extract can be useful as an alternative therapy to control MMP activity after corneal injury.

Protective effects of 4-nerolidylcatechol against genotoxicity induced by cyclophosphamide

In the present work we evaluated both the mutagenicity and antimutagenicity of the Pothomorphe umbellata root extract (PUE) and its isolated active principle, the 4-nerolidylcatechol (4-NC), in bone marrow cells of mice using the micronucleus test. Swiss male mice were orally treated for 4 days with PUE (200, 100 or 50mg/kg/day) or 4-NC (50, 25 or 12.5mg/kg/day) prior to exposition with a single dose (200mg/kg) of cyclophosphamide (CP), 24h after the end of the treatment. The results demonstrated that the PUE and 4-NC did not have any mutagenic effect on mouse bone marrow cells; quite the opposite, there was a protective effect against genotoxicity induced by cyclophosphamide. Taken together, under the conditions tested herein, mice treated with PUE and 4-NC showed, in a dose-dependent manner, protective effect against CP-induced genotoxicity. Due to their ability to prevent chromosomal damage, with apparent low toxicity and cost, PUE or pure 4-NC are likely to open a field of interest concerning their possible use in clinical applications.