Constituents of the leaves and twigs of Elaeagnus umbellata and their proliferative effects on human keratinocyte HaCaT cells

Undescribed glucosylceramide, flavonol triglycoside, and oleanane saponin from the halophyte Agathophora alopecuroides: Promising candidates for stimulating ceramide synthesis

The phytochemical study of Agathophora alopecuroides (Chenopodiaceae) led to the isolation of previously undescribed glucosylceramide, flavonol triglycoside, and triterpene oleanane saponin, together with eight known compounds. Their structures were elucidated using NMR analysis and HR-MS as (2'R, 12E) N-[(2S, 3S, 4R)-1-(β-D-glucopyranosyloxy)-3,4-dihydroxy-octadec-2-yl]-2-hydroxytetracos-12-enamide, namely Agathophamide A; isorhamnetin-3-O-[β-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→6)]-β-D-galactopyranoside, namely Agathophoroside A; and 3-O-[4'-(β-D-xylopyranosyl)-β-D-glucuronopyranosyl]-28-O-β-D-glucopyranosyl-olean-12-en-3β-ol-28-oic acid, namely Solysaponin A. We evaluated the effect of extract and isolates on ceramide levels via the up-regulated expression of the enzyme for ceramide synthesis in HaCaT keratinocytes. Interestingly, the study results revealed that the methanol extract of A. alopecuroides, together with some isolated compounds significantly up-regulated the mRNA expression of ceramide synthase-3 by 1.2- to 4.3-fold compared with the control in HaCaT cells. These findings indicate that the halophyte A. alopecuroides is a promising source of candidate compounds that can contribute to ceramide synthesis via the up-regulated expression levels of ceramide synthase-3 in the ceramide synthesis pathway.

The Modulatory Influence of Plant-Derived Compounds on Human Keratinocyte Function

The plant kingdom is a rich source of secondary metabolites with numerous properties, including the potential to modify keratinocyte biology. Keratinocytes are important epithelial cells that play a protective role against various chemical, physical and biological stimuli, and participate in reactive oxygen scavenging and inflammation and wound healing processes. The epidermal cell response may be modulated by phytochemicals via changes in signal transduction pathways. Plant extracts and single secondary compounds can possess a high antioxidant capacity and may suppress reactive oxygen species release, inhibit pro-apoptotic proteins and apoptosis and activate antioxidant enzymes in keratinocytes. Moreover, selected plant extracts and single compounds also exhibit anti-inflammatory properties and exposure may result in limited production of adhesion molecules, pro-inflammatory cytokines and chemokines in keratinocytes. In addition, plant extracts and single compounds may promote keratinocyte motility and proliferation via the regulation of growth factor production and enhance wound healing. While such plant compounds may modulate keratinocyte functions, further in vitro and in vivo studies are needed on their mechanisms of action, and more specific toxicity and clinical studies are needed to ensure their effectiveness and safety for use on human skin.

Boesenbergia rotunda extract accelerates human keratinocyte proliferation through activating ERK1/2 and PI3K/Akt kinases

Boesenbergia rotunda (BR) has long been used as tradition medicine. For its pharmacological effects on wound healing, previous studies in an animal model provided convincing results that the ethanolic extract from the rhizome of this plant can stimulate wound healing. However, the mechanism about how this plant promotes wound healing at the molecular level has not been elucidated. As a step towards the development of wound healing agents, our current study utilized a human keratinocyte cell line (HaCaT) as an in vitro model to define the potential molecular mechanisms of BR extract in enhancing wound-healing. Our HPLC results showed that BR extract contained kaempferol as one of its potential compounds. The extract strongly promoted wound healing of HaCaT cell monolayer. This effect was eventually defined to be regulated through the ability of BR extract to induce cell proliferation. At the signaling level, we discovered that BR extract rapidly activated ERK1/2 and Akt phosphorylation upon the addition of the extract. Additionally, our experiments where specific inhibitors of MEK (U0126) and PI3K (LY294002) were utilized verified that BR enhanced cell proliferation and wound healing through stimulating the MAPK and PI3K/Akt signal transduction pathways. Moreover, direct inhibition of keratinocyte DNA synthesis by mitomycin C (MMC) could completely block the proliferative effects of BR extract. Nevertheless, data from Transwell migration assay revealed that BR extract did not promote keratinocyte migration. Altogether, we provided more evidence that BR possesses its wound healing-promoting action through the activation of proliferation and survival pathways, and our study suggests that BR is an interesting candidate to be developed as a wound healing-promoting agent.

Antioxidant Activity of Compounds Isolated from Elaeagnus umbellata Promotes Human Gingival Fibroblast Well-Being

Four new triterpenoid bidesmosidic saponins (1-4) and a sesquiterpenoid glucoside (5), together with nine known phenolic compounds (6-14), were isolated from the fruits of Elaeagnus umbellata. Their structures were elucidated using 1D and 2D NMR spectroscopy and mass spectrometry data. The antioxidant capability of the isolated compounds was evaluated in human gingival fibroblasts. Compound 6 decreased ROS production and promoted cell proliferation. It also counteracted the cell cycle blockade induced by a low concentration of H2O2 decreasing the expression of p21 and CDKN2A (p16INK4A). Compound 6 decreased the expression of inflammatory cytokines (IL-6 and IL-8) in response to inflammatory stimuli, supporting its possible use in periodontitis lesions.