Hepatoprotective effects of Limonium tetragonum, edible medicinal halophyte growing near seashores

Biological activities and ecological aspects of Limonium pruinosum (L.) collected from Wadi Hof Eastern Desert, Egypt, as a promising attempt for potential medical applications

Very few researchers have focused on the biological efficacy of Limonium plants. In this concern, no investigations were commenced to delve into the in vitro and ex vivo biological actions of Limonium pruinosum in Egypt. Therefore, this work aims to assess for the first time the antimicrobial, antioxidant, and antitumor activities of Limonium pruinosum extract in addition to studying its ability to suppress the transcription of cell cycle–stimulating genes. L. pruinosum ethyl acetate extract exhibits considerable antibacterial and antibiofilm activity versus E. coli ATCC 25922 and Staphylococcus aureus ATCC 25923. Results revealed that L. pruinosum exerts antioxidant effectiveness concerning DPPH, nitric oxide (NO), and hydroxyl radical (OH) scavenging ability with an IC50 (35.88 ± 2.2, 51.31 ± 1.06, and 65.87 ± 1.19 μg/mL) respectively. The results proved the effectiveness of L. pruinosum in closing wounds in gastric epithelial cells (GES-1) by (79.9343 ± 1.98%) compared with control (68.3637 ± 2.32%) in 48 h. Additionally, L. pruinosum had anticancer activity contrary to breast cancer MCF-7 and liver cancer HepG-2 cell lines with IC50 values of 96.73 ± 2.18 and 81.81 ± 0.99 μg/mL, respectively, while it had no cytotoxic activity against (Wi-38) normal cells. Also, L. pruinosum extract provoked considerable early- and late-apoptotic cell populations and was effective in inducing cell death of MCF-7. Our findings evoked that L. pruinosum has promising antibacterial, antioxidant, and wound healing activities and a good breast tumor suppressor arresting the cell cycle-stimulating genes, which may be an auspicious approach for the treatment of breast cancer.

Protective effects of halophyte complex extract against UVB-induced damage in human keratinocytes and the skin of hairless mice

Limonium tetragonum, Triglochin maritimum, Artemisia scoparia and red ginseng have been used as folk remedies for treating a variety of diseases. In the current study, the protective effects of halophyte and red ginseng against ultraviolet (UV)-induced skin damage were investigated. Halophyte red ginseng complex extract (HRCE) was prepared and its effects on UV-B irradiated human keratinocytes and mouse skin were studied through ELISA, Western blotting immunofluorescence and histological staining. HRCE inhibited peroxide-induced damage in human keratinocytes. HRCE also inhibited UVB-induced collagen and elastin degradation in human keratinocytes and mouse skin. In addition, HRCE inhibited mast cell infiltration in the skin of mice irradiated with UVB light. This effect was likely due to HRCE inhibiting the activation of MAPK and NF-κB. By protecting the skin from UVB-induced skin damage, HRCE has the potential to be used in the treatment and prevention of UV-induced skin damage and photoaging.

Suaeda vermiculata Aqueous-Ethanolic Extract-Based Mitigation of CCl4-Induced Hepatotoxicity in Rats, and HepG-2 and HepG-2/ADR Cell-Lines-Based Cytotoxicity Evaluations

Suaeda vermiculata, an edible halophytic plant, used by desert nomads to treat jaundice, was investigated for its hepatoprotective bioactivity and safety profile on its mother liquor aqueous-ethanolic extract. Upon LC-MS (Liquid Chromatography-Mass Spectrometry) analysis, the presence of several constituents including three major flavonoids, namely quercetin, quercetin-3-O-rutinoside, and kaempferol-O-(acetyl)-hexoside-pentoside were confirmed. The aqueous-ethanolic extract, rich in antioxidants, quenched the DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, and also showed noticeable levels of radical scavenging capacity in ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid) assay. For the hepatoprotective activity confirmation, the male rat groups were fed daily, for 7 days (n = 8/group, p.o.), either carboxyl methylcellulose (CMC) 0.5%, silymarin 200 mg/kg, the aqueous-ethanolic extract of the plant Suaeda vermiculata (100, 250, and 500 mg/kg extract), or quercetin (100 mg/kg) alone, and on day 7 of the administrations, all the animal groups, excluding a naïve (250 mg/kg aqueous-ethanolic extract-fed), and an intact animal group were induced hepatotoxicity by intraperitoneally administering carbon tetrachloride (CCl₄). All the animals were sacrificed after 24 h, and aspartate transaminase and alanine transaminase serum levels were observed, which were noted to be significantly decreased for the aqueous-ethanolic extract, silymarin, and quercetin-fed groups in comparison to the CMC-fed group (p < 0.0001). No noticeable adverse effects were observed on the liver, kidney, or heart's functions of the naïve (250 mg/kg) group. The aqueous-ethanolic extract was found to be safe in the acute toxicity (5 g/kg) test and showed hepatoprotection and safety at higher doses. Further upon, the cytotoxicity testings in HepG-2 and HepG-2/ADR (Adriamycin resistant) cell-lines were also investigated, and the IC₅₀ values were recorded at 56.19±2.55 µg/mL, and 78.40±0.32 µg/mL (p < 0.001, Relative Resistance RR 1.39), respectively, while the doxorubicin (Adriamycin) IC₅₀ values were found to be 1.3±0.064, and 4.77±1.05 µg/mL (p < 0.001, RR 3.67), respectively. The HepG-2/ADR cell-lines when tested in a combination of the aqueous-ethanolic extract with doxorubicin, a significant reversal in the doxorubicin's IC₅₀ value by 2.77 folds (p < 0.001, CI = 0.56) was noted as compared to the cytotoxicity test where the extract was absent. The mode of action for the reversal was determined to be synergistic in nature indicating the role of the aqueous-ethanolic extract.

Anticatabolic and Anti-Inflammatory Effects of Myricetin 3-O-β-d-Galactopyranoside in UVA-Irradiated Dermal Cells via Repression of MAPK/AP-1 and Activation of TGFβ/Smad

UV irradiation is one of the main causes of extrinsic skin aging. UV-mediated skin aging, also known as photoaging, causes excessive breakdown of extracellular matrix which leads skin to lose its elasticity and strength. Several phytochemicals are known to exert anti-photoaging effects via different mechanisms, partly due to their antioxidant properties. The current study has been carried out to determine the potential anti-photoaging properties of myricetin 3-O-β-d-galacto-pyranoside (M3G), a flavonol glycoside isolated from L. tetragonum, in UVA-irradiated in vitro models; HaCaT keratinocytes and human dermal fibroblasts (HDFs). UVA-induced changes in MMP-1 and collagen production have been observed in HaCaT keratinocytes and HDFs. Further, UVA-induced activation of MAPK signaling, and pro-inflammatory cytokine production have been investigated. TGFβ/Smad pathway has also been analyzed in UVA-irradiated HDFs. Treatment with M3G reversed the UVA-induced changes in MMP-1 and collagen production both in HaCaT keratinocytes and HDFs. UVA-mediated activation of p38, ERK and JNK MAPK activation was also inhibited by M3G treatment in HaCaT keratinocytes. In HDFs, M3G was able to upregulate the TGFβ/Smad pathway activation. In addition, M3G downregulated the UVA-induced pro-inflammatory cytokines in keratinocytes and HDFs. It has been suggested that the M3G has exerted potential antiphotoaging properties in vitro, by attenuating UVA-induced changes in MMP-1 and collagen production in keratinocytes and dermal fibroblasts.

Anti-obesity Effect of Halophyte Crop, Limonium tetragonum in High-Fat Diet-Induced Obese Mice and 3T3-L1 Adipocytes

Halophyte Limonium tetragonum has recently been of interest in Korea for its nutritional value and salty taste which made it an ideal vegetable. In this study, the potential of L. tetragonum preventing excess weight gain, obesity and the related health problem has been evaluated in vitro and in vivo. The treatment with 100 mg/kg of L. tetragonum EtOAc soluble fraction (EALT) apparently prevented the body weight gain, adipose tissue weight gain, and the increase of triglyceride and total cholesterol level in mice fed a high-fat diet for 8 weeks. In addition, both glucose tolerance and insulin resistance in dietary obese mice were improved by EALT administration. A marked decrease in adipocyte differentiation was observed in the EALT (50 µg/mL)-treated 3T3-L1 cells, which was mediated by the suppression of adipogenesis-related transcription factors including peroxisome proliferator-activated receptor (PPAR) γ, CCAAT/enhancer binding protein (C/EBP)α, and Sterol regulatory element binding protein-1 (SREBP-1) and adipocyte-specific proteins such as fatty acid synthase (FAS), lipoprotein lipase (LPL), and adipocyte fatty acid-binding protein (aP2). The major components contained in EALT were identified as (-)-epigallocatechin-3-(3″-O-methyl) gallate, (-)-epigallocatechin-3-gallate, and myricetin-3-O-β-D-galactopyranoside based on its phytochemical analysis. Results suggested that EALT might be available as functional crop and bioactive diet supplement for the prevention and/or treatment of obesity.

The Standardized Extract of Limonium tetragonum Alleviates Chronic Alcoholic Liver Injury in C57Bl/6J Mice

Background:

In traditional folk medicine, Limonium tetragonum is used in the treatment of uterine hemorrhage, tinnitus, and oligomenorrhea.

Objective:

This study aimed to identify the therapeutic effect of L. tetragonum EtOAc extract (EALT) on liver of mice with chronic alcohol poisoning.

Materials and Methods:

C57BL/6J mice were administered 100 mg/kg of EALT with a single binge ethanol/Lieber-DeCarli liquid diet for 8 weeks.

Results:

The chronic-binge ethanol diet induced a significant increase in liver marker enzyme activities. Coadministration of EALT reversed the elevation of serum total cholesterol and triglyceride as well as aspartate aminotransferase and alanine aminotransferase due to chronic alcohol consumption. Histologic findings including markedly attenuated fat accumulation in hepatocytes were observed in EALT-treated mice. EALT supplementation prevented alcoholic liver injury through attenuation of inflammatory mediators such as toll-like receptor-4, cytochrome P4502E1, and cyclooxygenase-2, and inflammatory cytokine interleukin-6.

Conclusion:

Results provided direct experimental evidence for the hepatoprotective effect of EALT in the NIAAA mouse model. Therapeutic attempts with the L. tetragonum extract might be useful in the management of alcoholic liver disease.

SUMMARY

Halophyte Limonium tetragonum has recently been of interest in Korea for its nutritional value and salty taste which made it an ideal vegetable

Phytochemical analysis of L. tetragonum EtOAc extract (EALT) resulted in nine compounds including catechins and myricetin glycosides as main components

Administration of EALT for 8 weeks showed hepatoprotective effect on Lieber-DeCarli diet-fed mouse model

A significant decrease in liver marker enzymes and inflammatory mediators was also detected.

Abbreviations used: EALT: L. tetragonum EtOAc extract; TC: Total cholesterol; TG: Triglyceride; ROS: Reactive oxygen species; CYP2E1: Cytochrome P4502E1; TLR-4: Toll-like receptor-4; COX-2: Cyclooxygenase-2.

Identification of Hepatoprotective Constituents in Limonium tetragonum and Development of Simultaneous Analysis Method using High-performance Liquid Chromatography

Background:

Limonium tetragonum, a naturally salt-tolerant halophyte, has been studied recently and is of much interest to researchers due to its potent antioxidant and hepatoprotective activities.

Objective:

In the present study, we attempted to elucidate bioactive compounds from ethyl acetate (EtOAc) soluble fraction of L. tetragonum extract. Furthermore, the simultaneous analysis method of bioactive EtOAc fraction of L. tetragonum has been developed using high-performance liquid chromatography (HPLC).

Materials and Methods:

Thirteen compounds have been successfully isolated from EtOAc fraction of L. tetragonum, and the structures of 1–13 were elucidated by extensive one-dimensional and two-dimensional spectroscopic methods including ¹H-NMR, ¹³C-NMR, ¹H-¹H COSY, heteronuclear single quantum coherence, heteronuclear multiple bond correlation, and nuclear Overhauser effect spectroscopy. Hepatoprotection of the isolated compounds against liver fibrosis was evaluated by measuring inhibition on hepatic stellate cells (HSCs) undergoing proliferation.

Results:

Compounds 1–13 were identified as gallincin (1), apigenin-3-O-β-D-galactopyranoside (2), quercetin (3), quercetin-3-O-β-D-galactopyranoside (4), (−)-epigallocatechin (5), (−)-epigallocatechin-3-gallate (6), (−)-epigallocatechin-3-(3″-O-methyl) gallate (7), myricetin-3-O-β-D-galactopyranoside (8), myricetin-3-O-(6″-O-galloyl)-β-D-galactopyranoside (9), myricetin-3-O-α-L-rhamnopyranoside (10), myricetin-3-O-(2″-O-galloyl)-α-L-rhamnopyranoside (11), myricetin-3-O-(3″-O-galloyl)-α-L-rhamnopyranoside (12), and myricetin-3-O-α-L-arabinopyranoside (13), respectively. All compounds except for 4, 8, and 10 are reported for the first time from this plant.

Conclusion:

Myricetin glycosides which possess galloyl substituent (9, 11, and 12) showed most potent inhibitory effects on the proliferation of HSCs.

SUMMARY

In the present study, we have successfully isolated 13 compounds from bioactive fraction of Limonium tetragonum. The structures of compounds isolated have been fully elucidated, and hepatoprotective activities of compounds against liver fibrosis were evaluated by measuring inhibition on hepatic stellate cells undergoing proliferation. Furthermore, the simultaneous analysis method of bioactive ethyl acetate fraction of L. tetragonum has been developed using HPLC. Ten compounds identified herein are reported for the first time from this plant.

Abbreviations used: HSQC: Heteronuclear single quantum coherence; HMBC: Heteronuclear multiple bond correlation; NOESY: Nuclear Overhauser effect spectroscopy; EGCG: Epigallocatechin-3-gallate; EGC: Epigallocatechin; HSC: Hepatic stellate cell; MTT: 3-(4,5-dimethylthiazol-2-yl)-2.5-diphenyltetrazolium bromide.

Anti-Melanogenic Effects of Flavonoid Glycosides from Limonium tetragonum (Thunb.) Bullock via Inhibition of Tyrosinase and Tyrosinase-Related Proteins

Overproduction and stimulation of tyrosinase result in increased melanogenesis of which several skin disorders such as freckles, spots, and hyperpigmentation appear as complications. Limonium tetragonum is a halophyte well-known for its antioxidative properties. This study investigated the anti-melanogenic effects of solvent-partitioned L. tetragonum extracts (LTEs) and its bioactive constituents, two isolated flavonoid glycosides. Current study followed a set of experiments on B16-F10 mouse melanoma cell model with a focus on tyrosinase activity and production. The anti-melanogenic capacity of LTEs was confirmed by their tyrosinase inhibitory effects, prevention of DOPA oxidation, and suppression of melanin production. The inhibition of tyrosinase and DOPA oxidation by LTEs was suggested to be related with the downregulation of microphthalmia-associated transcription factor, tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2, verified with mRNA and protein expression levels. Among all tested LTEs, 85% aq. MeOH and n-BuOH were found to be the most active fractions which later yielded the two known compounds, myricetin 3-galactoside and quercetin 3-O-β-galactopyronaside. The anti-melanogenic potential of the compounds were confirmed by their tyrosinase inhibitory effects. These results suggested that L. tetragonum may serve as a potential source of bioactive substances with effective anti-melanogenesis properties.

Protective Effects of Ethyl Acetate Soluble Fraction of Limonium tetragonum on Diethylnitrosamine-Induced Liver Fibrosis in Rats

Diethylnitrosamine (DEN) is a potent toxic material that can cause necrosis and subsequent fibrosis in the liver. Based on the previously reported hepatoprotective effect of Limonium tetragonum against the proliferation of hepatic stellate cells, we tested the EtOAc soluble fraction of L. tetragonum extract (EALT) in a DEN-induced hepatotoxic rat model. The development of hepatotoxicity including mononuclear cell infiltration and fibrosis induced by intraperitoneal injections of DEN (70 mg/2 mL/kg body weight (b.w.) per week) was observed at 4, 6 and 8 weeks after the first DEN treatment. Administration of EALT (200 mg/kg body weight, per os (p.o.)) induced significant reductions in serum alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), and triglycerides (TG) in DEN-injected rats. Increased oxidative stress in DEN-induced liver fibrosis rats was diminished by EALT treatment through a decrease in malondialdehyde (MDA) and increase in superoxide dismutase (SOD). Histologic findings that included markedly attenuated mononuclear cell infiltration and fibrosis could be observed in liver samples from the EALT-treated groups. An extract of Hovenia dulcis fruit and Sylimarin were used as positive controls. The present study provides direct experimental evidence for EALT attenuated hepatic injury and fibrosis in DEN-treated mice. The L. tetragonum EtOAc fraction might be useful in treating fibrotic liver diseases.

Inhibition of MMP-2 and MMP-9 Activities by Limonium tetragonum Extract

Matrix metalloproteinases (MMPs) are crucial extracellular matrices degrading enzymes that take important roles in metastasis of cancer progression as well as other significant conditions such as oxidative stress and hepatic fibrosis. Natural products are on the rise for their potential to provide remarkable health benefits. In this context, halophytes have been of interest in the nutraceutical field with reported instances of isolation of bioactive compounds. In this study, Limonium tetragonum, an edible halophyte, was studied for its ability to inhibit MMP-2 and -9 using HT1080 fibrosarcoma cells. Results showed that L. tetragonum extract was able to inhibit the enzymatic activity and mRNA expression of MMP-2 and -9 according to gelatin zymography and RT-PCR assays, respectively, but it was not able to significantly change the MMP pathway related factors such as tissue inhibitors of metalloproteinases. Also, Mitogen-activated protein kinases pathway-related protein levels and their phosphorylation were assayed. While the phosphorylated p38 levels were decreased, extracellular signal-regulated kinase and c-Jun N-terminal kinase were not affected by L. tetragonum treatment. In conclusion, it was suggested that L. tetragonum contains substances acting as MMP inhibitors on enzymatic activity rather than intracellular pathway intervention, which could be useful for further utilization of L. tetragonum as a source for anti-MMP agents.