Effects of a Phenol-Enriched Purified Extract from Olive Mill Wastewater on Skin Cells

Abstract

Olive trees (Olea europaea) and their processed products, such as olive oil, play a major role in the Mediterranean way of life. Their positive impact on human health is being intensely investigated. One research topic is the identification of new application areas of olive mill wastewater (OMWW). OMWW is characterized by the high content of polyphenols possessing many positive health effects. Thus, the phenol-enriched OMWW extract offers the potential for the treatment of skin disorders and for cosmetic application. The aim of the present study was to evaluate cell viability and proliferation, the anti-inflammatory and anti-oxidative properties of a phenol-enriched OMWW extract on an immortal keratinocyte cell line (HaCaT cells). Moreover, the influence on the growth of various microorganisms was investigated; furthermore, the effects on normal human epidermal keratinocytes (NHEK) and human melanoma cells (A375) were studied in a commercially available tumor invasion skin model. The phenol-enriched OMWW extract showed excellent antimicrobial activity. Moreover, a noticeable reduction in reactive oxygen species formation as well as Interleukin-8 release in HaCaT cells were observed. Finally, the inhibited growth of A375 melanoma nodules in the melanoma skin model could be shown. Our results indicate that the OMWW extract is a promising ingredient for dermal applications to improve skin health and skin protection as well as having a positive impact on skin ageing.

Polyphenolic Fraction from Olive Mill Wastewater: Scale-Up and in Vitro Studies for Ophthalmic Nutraceutical Applications

“…Our results are in accordance with Schlupp et al (2019) who reported the antioxidant activity of a phenol-enriched OMWW extract was able to reduce the formation of free radicals in vitro [52]. Similar results were obtained by Schaffer et al (2007) who demonstrated that hydroxytyrosol-rich olive mill wastewater extract was able to protect brain cells from oxidative damage [53].…”

Olive Fruit and Leaf Wastes as Bioactive Ingredients for Cosmetics—A Preliminary Study

“…To the best of our knowledge, this is the first study that explores the effects of these commercial extracts on skin cell lines by MTT assay. Nevertheless, Schlupp et al investigated the viability of keratinocytes by WST-1 assay after exposure to an olive mill wastewater extract [77]. The results revealed a considerable decrease in HaCaT viability for the extract dilution of 1:100 (70.9%) after 72 h. Otherwise, extract dilutions from 1:200 to 1:1000 showed HaCaT viabilities above 100% [77].…”

“…Nevertheless, Schlupp et al investigated the viability of keratinocytes by WST-1 assay after exposure to an olive mill wastewater extract [77]. The results revealed a considerable decrease in HaCaT viability for the extract dilution of 1:100 (70.9%) after 72 h. Otherwise, extract dilutions from 1:200 to 1:1000 showed HaCaT viabilities above 100% [77]. The present results are also in line with those obtained by Lameirão et al for chestnut extracts obtained by ultrasound-assisted extraction [33].…”

Potential of Olive Oil Mill Wastewater as a Source of Polyphenols for the Treatment of Skin Disorders: A Review

“…Richard et al showed that an extract of OMW containing 42% total phenolic compounds, including 2.5% HT, reduced by up to 72% the level of TNF-α, iNOS, IL-6, and IL-1β in lipoxygenase (LPS)-activated macrophages, concluding that HT was the main bioactive phenolic compound involved . The action of OMWs on inflammatory cytokines was confirmed by Schlupp: In the immortal keratinocyte cell line (HaCaT cells) treated with an extract of OMW containing 2.5 mg/L HT, 0.8 mg/L tyrosol, and 1 mg/L verbascoside, IL-8 levels were reduced by 73% via inhibition of the NF-κB pathway . The activity of an OMW extract (in test concentrations of 100–400 ng/μL) on normal human epidermal keratinocytes (NHEKs) was evidenced by a noticeable reduction in reactive oxygen species (ROS) and IL-8 release in HaCaT cells.…”

“…acnes (anaerobic Gram positive). The authors concluded that the antibacterial activity could be attributed to the high content of HT and oleuropein in the OMW extract and suggested that they could be used as preservatives in dermatological formulations . In terms of individual compounds, HT was found to be active against P.…”