Protection of DNA and membrane from γ-radiation induced damage by the extract of Acorus calamus Linn.: An in vitro study

Mechanistic role and potential of Ayurvedic herbs as anti-aging therapies

INTRODUCTION

Medicinal plants and herbs are the most important part of the Ayurveda. The term Rasayana in Charaka Samhita confers long life, youthfulness, strong body, freedom from diseases and the plants mentioned in Rsayana possess antiaging property. Aging is the collective term used for the complex detrimental physiological changes that reduce the functional ability of the cell. Oxidative stress, telomeres shortening, inflammation, and mitochondrial dysfunction are the main factors that regulate the aging process. Chronological aging is an irreversible process but the factors causing biological aging can be controlled. Ayurvedic herbs are better for the management of age-related problems. There are several natural bioactive agents present in plants that can delay the aging process in humans. They trigger actions like enhancing gene longevity and telomerase activity, ROS scavenging furthermore regeneration of tissues.

CONTENT

The plants mentioned in the Rasayana of Ayurveda have antiaging potential and can be used to solve modern problems related to aging. Some Ayurvedic plants and their antiaging potential has explained in this review. The main causes of aging, medicinal plants and their use as potential antiaging mediator are covered in this study.

SUMMARY

The process of aging is still an enigma. It is a complex, irretrievable, dynamic process that involves a number of factors and is subject to a number of environmental and genetic influences. Rasayana aspect has not been much investigated in clinical trials. Aging is considered to result from free radical damage. According to Charaka, Rasayana drugs open the partially or fully blocked channels. Many Rasayanas show free radical scavenging activity and has the potential to mitigate the effects of aging. It gives an overview of the significance of Ayurvedic medicinal plants as a source of inspiration and the use of these plants as remedies for antiaging.

OUTLOOK

This study briefly outlooks the causes of aging and how medicinal plants can be used to reverse the aging process. In this study, we discussed the antiaging potential and mechanistic roles of Ayurvedic herbs. These herbs have the properties to slow down the natural process of aging and can successfully manage common age-related problems.

Pterocarpus santalinus L. extract mitigates gamma radiation-inflicted derangements in BALB/c mice by Nrf2 upregulation

Plant-based natural extracts contain several nutrients and bioactive compounds, such as phenolics and flavonoids, that possess various health-promoting activities. This study investigated the effects of polyphenols from Pterocarpus santalinus hydroalcoholic extract (PSHE) against gamma radiation-induced derangements via the upregulation of Nrf2. Ultra High Performance Liquid Chromatography Coupled to High Resolution Mass Spectrometry (UHPLC-HRMS/MS) analysis was performed to identify the possible radioprotectors. In vivo and in vitro studies, namely Real-Time-PCR (RT-PCR) analysis, Reactive Oxygen Species (ROS) scavenging activity, lipid peroxidation and GSH levels, DNA damage and cell death studies, anti-inflammatory (Sandwich ELISA), immunomodulatory studies (antibody staining), and model free radical scavenging assays, were performed. Vanillic acid, protocatechuic acid, para-hydroxybenzoic acid, chlorogenic acid, TNF-α inhibitor (Eudesmin), isoflavone (Daidzein 7-o-glucoside), astragalin (Kaempferol 3-o-glycoside), and other polyphenols were identified in PSHE using UHPLC-HRMS/MS analysis. Prophylactic administration of PSHE (-1 h) rendered more than 33% survival in mice exposed to 8 Gy whole-body-irradiation with increased mice survival and recovery of bone marrow and spleen cellularity. Real-time RT-PCR analysis showed that PSHE treatment (50 µg/mL) upregulated Nrf2, HO-1, and GPX-1 in mice splenocytes. At 50 µg/mL, PSHE reduced ROSscavenging activity, mitochondrial and spleen membrane lipid peroxidation levels, DNA damage, and cell death, and increased GSH levels. At 10 µg/mL, PSHE treatment diminished the content of IL-6 and TNF-α. At 50 µg/mL, PSHE suppressed lymphocyte proliferation. These findings indicate that polyphenols of PSHE possess marked antioxidant, anti-inflammatory, and immunomodulatory capacities, which play important roles in the prevention of radiation damage.

Telomeres, DNA Damage and Ageing: Potential Leads from Ayurvedic Rasayana (Anti-Ageing) Drugs

Ageing, while a relentless, unidirectional and pleiotropic phenomenon of life, is a key trigger for several age-related disorders, such as cancer, cataract, osteoporosis, hypertension, cardiovascular (CV), metabolic and even neurodegenerative ailments, including Alzheimer's (AD) and Parkinson's (PD) disease [1] [...].

Celastrol Alleviates Gamma Irradiation-Induced Damage by Modulating Diverse Inflammatory Mediators

The present study aimed to explore the possible radioprotective effects of celastrol and relevant molecular mechanisms in an in vitro cell and in vivo mouse models exposed to gamma radiation. Human keratinocytes (HaCaT) and foreskin fibroblast (BJ) cells were exposed to gamma radiation of 20 Gy, followed by treatment with celastrol for 24 h. Cell viability, reactive oxygen species (ROS), nitric oxide (NO) and glutathione (GSH) production, lipid peroxidation, DNA damage, inflammatory cytokine levels, and NF-κB pathway activation were examined. The survival rate, levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in blood, and p65 and phospho-p65 expression were also evaluated in mice after exposure to gamma radiation and celastrol treatment. The gamma irradiation of HaCaT cells induced decreased cell viability, but treatment with celastrol significantly blocked this cytotoxicity. Gamma irradiation also increased free radical production (e.g., ROS and NO), decreased the level of GSH, and enhanced oxidative DNA damage and lipid peroxidation in cells, which were effectively reversed by celastrol treatment. Moreover, inflammatory responses induced by gamma irradiation, as demonstrated by increased levels of IL-6, TNF-α, and IL-1β, were also blocked by celastrol. The increased activity of NF-κB DNA binding following gamma radiation was significantly attenuated after celastrol treatment. In the irradiated mice, treatment with celastrol significantly improved overall survival rate, reduced the excessive inflammatory responses, and decreased NF-κB activity. As a NF-κB pathway blocker and antioxidant, celastrol may represent a promising pharmacological agent with protective effects against gamma irradiation-induced injury.

Protective effects of celastrol against γ irradiation-induced oxidative stress in human umbilical vein endothelial cells

High-dose ionizing radiation can cause harmful effects on the cardiovascular system. Notably, endothelial cells are critical targets in radiation-induced damage. γ radiation exerts its biological effects through the radiolysis of water, which further generates ROS and induces lipid peroxidation and DNA damage. The present study aimed to evaluate the potential protective effects of celastrol against γ radiation-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). HUVECs were exposed to γ radiation at different doses with or without celastrol treatment. Cell viability and cytotoxicity, migratory ability, ROS production, lipid peroxidation, oxidative DNA damage and antioxidative enzyme levels were evaluated in HUVECs at 24 h post-irradiation. It was observed that HUVECs exhibited decreased cell viability, increased cytotoxicity and a decreased migratory ability after exposure to 20-Gy γ radiation. Celastrol treatment concentration-dependently reversed these effects. γ irradiation was also demonstrated to increase the production of ROS, enhance lipid peroxidation and oxidative DNA damage and decrease the levels of SOD, catalase, GST and GPx in HUVECs. These detrimental effects were blocked by treatment with celastrol for 24 h. These data suggested that celastrol not only attenuated γ radiation-induced cytotoxicity, but also effectively blocked oxidative stress in HUVECs. As an antioxidant agent, celastrol may have potential protective effects in HUVECs against γ irradiation-induced injury.

In Vitro Bioassay-guided Isolation of Radioprotective Fractions from Extracts of Pinus koraiensis Bark

Objective

The aim of this study was to evaluate radioprotective effect of extracts of Pinus koraiensis bark and its fractions on rat splenocytes by using bioassay-guided isolation in order to obtain the best active fraction.

Materials and Methods

P. koraiensis bark was ground and extracted with water, 40% acetone, 95% ethanol. Bio-guided assay was selected as an evaluation method to further fractionate radioprotective component from P. koraiensis bark extract. Total phenolic and flavonoid contents in fractions were also measured. Rat splenocytes were prepared by using mechanical trituration method. DNA damage was assessed as comet parameters (tail DNA%, tail length, tail moment, olive tail moment). The levels of malondialdehyde (MDA), and activity of superoxide dismutase (SOD), catalase (CAT) in cultured rat splenocytes were also measured.

Results

The radioprotective effects decreased from rutin >95% ethanol extracts of Pinus koraiensis bark (95EEP) >40AEP > WEP. The stimulating effects decreased from rutin > n-butanol extract (NBE) > EAE. The results demonstrate that there exists toxic ingredients (PEE and dichloromethane extract), proliferative-promoting, radioprotective component (EAE and NBE) in 95EEP. fraction eluted from n-butanol fractions of 95EEP with 50% methanol solution (NBEPKB-50ME), a fraction of NBE result from bio-guided isolation, demonstrates good radioprotective efficacy on rat splenocytes. NBEPKB-50ME pretreated rat splenocytes demonstrated progressively reduced levels of MDA when compared with γ-ray exposed cells. Different dose of NBEPKB-50ME pretreatment with 8 Gy-irration showed an increase in enzymatic antioxidant.

Conclusions

Proliferative-promoting efficacy, radioprotective effect of different solvents extracts of the bark of P. koraiensis were investigated in this work. NBEPKB-50ME was the best elution in NBE, especially in restoring SOD, CAT activities, content of GSH, decreasing DNA damage.

SUMMARY

The radioprotective effects decreased from rutin > 95EEP > 40AEP > WEP. The extract of Petroleum ether, dichloromethane extract (DME) of 95% ethanol extract of P. koraiensis (PEE, DME) show toxic effect on rat splenocytes. The extract of Ethyl acetate, n-butanol extract of 95% ethanol extract of P. koraiensis (EAE, NBE) show proliferative-promoting, radioprotective effect on rat splenocytesSingle-cell gel electrophoresis was used to evaluate the spleen cell DNA damage parameters affected by gamma-radiation and addition of best component NBEPKB-50Me from extract of P. koraiensis barkNBEPKB-50ME pretreatment with 8 Gy-irradiation showed an increase in enzymatic antioxidant capacity. NBEPKB-50ME pretreated (80, 160, 320, 480 mg/ml) rat splenocytes demonstrated progressively reduced levels of MDA when compared with g-ray exposed cells. Abbreviations used: MDA: Malondialdehyde; SOD: Superoxide dismutase; CAT: Catalase; PEE: Petroleum ether Extract; DME: Dichloromethane extract; EAE: Ethyl acetate extract; NBE: n-butanol extract; WAP: Water extracts of Pinus koraiensis bark; 40AEP: 40% acetone extracts of Pinus koraiensis bark; 95EEP: 95% ethanol extracts of Pinus koraiensis bark; TPC: Total phenolic content; TFC: Total flavonoid content; NBEPKB-50ME: Fraction eluted from n-Butanol fractions of 95EEP with 50% methanol solution.

Potential Protective Effects of Ursolic Acid against Gamma Irradiation-Induced Damage Are Mediated through the Modulation of Diverse Inflammatory Mediators

This study was aimed to evaluate the possible protective effects of ursolic acid (UA) against gamma radiation induced damage both in vitro as well as in vivo. It was observed that the exposure to gamma radiation dose- and time-dependently caused a significant decrease in the cell viability, while the treatment of UA attenuated this cytotoxicity. The production of free radicals including reactive oxygen species (ROS) and NO increased significantly post-irradiation and further induced lipid peroxidation and oxidative DNA damage in cells. These deleterious effects could also be effectively blocked by UA treatment. In addition, UA also reversed gamma irradiation induced inflammatory responses, as indicated by the decreased production of TNF-α, IL-6, and IL-1β. NF-κB signaling pathway has been reported to be a key mediator involved in gamma radiation-induced cellular damage. Our results further demonstrated that gamma radiation dose- and time-dependently enhanced NF-κB DNA binding activity, which was significantly attenuated upon UA treatment. The post-irradiation increase in the expression of both phospho-p65, and phospho-IκBα was also blocked by UA. Moreover, the treatment of UA was found to significantly prolong overall survival in mice exposed to whole body gamma irradiation, and reduce the excessive inflammatory responses. Given its radioprotective efficacy as described here, UA as an antioxidant and NF-κB pathway blocker, may function as an important pharmacological agent in protecting against gamma irradiation-induced injury.

Prevention of γ-radiation induced cellular genotoxicity by tempol: protection of hematopoietic system

Tempol (TPL) under in vitro conditions reduced the extent of gamma radiation induced membrane lipid peroxidation and disappearance of covalently closed circular form of plasmid pBR322. TPL protected cellular DNA from radiation-induced damage in various tissues under ex vivo and in vivo conditions as evidenced by comet assay. TPL also prevented radiation induced micronuclei formation (in peripheral blood leucocytes) and chromosomal aberrations (in bone marrow cells) in whole body irradiated mice. TPL enhanced the rate of repair of cellular DNA (blood leucocytes and bone marrow cells) damage when administered immediately after radiation exposure as revealed from the increased Cellular DNA Repair Index (CRI). The studies thus provided compelling evidence to reveal the effectiveness of TPL to protect hematopoietic system from radiation injury.

Critical evaluation of ayurvedic plants for stimulating intrinsic antioxidant response

Oxidative damage caused by free radicals plays an important role in the causation and progression of many diseases, including aging. Free-radical damage is countered by many mechanisms, including both active antioxidant enzymatic activity in our body and passive antioxidants. Antioxidant response of our body can accommodate increased oxidative damage in diseased states to a level but beyond that level, additional antioxidants are required to combat the increased stress. Apart from the regular dietary sources of antioxidants, many traditional herbal medicines demonstrate a potential to boost antioxidant activity. Rasayana chikitsa that deals with rejuvenation and revitalization is a branch of the Indian traditional medical system of ayurveda. We review some select herbs described in rasayana chikitsa that have been assessed by modern means for stimulating intrinsic antioxidant responses in humans. A critical evaluation of rasayana chikitsa will likely provide urgently needed, actual stimulants of our physiological antioxidant responses and not just more passive antioxidants to add to an already large catalog.

Protective effects of polysaccharides from soybean meal against X-ray radiation induced damage in mouse spleen lymphocytes

The aim of this study was to investigate radioprotective effect of the polysaccharides from soybean meal (SMP) against X-ray radiation-induced damage in mouse spleen lymphocytes. MTT and comet assay were performed to evaluate SMP's ability to prevent cell death and DNA damage induced by radiation. The results show that, X-ray radiation (30 KV, 10 mA, 8 min (4 Gy)) can significantly increase cell death and DNA fragmentation of mouse spleen lymphocytes. Pretreatment with SMP for 2 h before radiation could increase cell viability, moreover, the SMP can reduce X-ray radiation-induced DNA damage. The percentage of tail DNA and the tail moment of the SMP groups were significantly lower than those of the radiation alone group (p < 0.05). These results suggest SMP may be a good candidate as a radioprotective agent.

Modulation of phase-II enzyme activities in benzene treated ovariectomized rats

The aim of the study was to determine the influence of ovariectomy on phase II enzymes viz. glutathione-S-transferase (GST), glutathione peroxidase (GPX) and catalase (CAT) in liver and kidney of female rats treated with benzene. The results showed the significant decrease of the GST and GPX activity in benzene treated rats after ovariectomy. However progesterone supplementation stimulated the activity of GST and GPX in liver and kidney of benzene treated non ovariectomized and ovariectomized rats. Progesterone supplementation to benzene treated ovariectomized rats helps to gain in CAT activity. Our results on DNA damage using single cell gel electrophoresis also confirmed our findings on antioxidant enzymes. The results showed that lack of protective progesterone against benzene toxicity is reflected in alterations in antioxidant enzyme activities. However progesterone therapy to benzene treated ovariectomized rats results in activating the antioxidant defence system. Since female workers are engaged in industrial sector, these results are important from occupational health point of view. Benzene exposure affects their reproductive health. Nevertheless, it could be modulated by suitable hormonal therapy.

Study of DNA damage with a new system for irradiation of samples in a nuclear reactor

In this paper, we report results of a quantitative analysis of the effects of neutrons on DNA, and, specifically, the production of simple and double breaks of plasmid DNA in aqueous solutions with different concentrations of free-radical scavengers. The radiation damage to DNA was evaluated by electrophoresis through agarose gels. The neutron and gamma doses were measured separately with thermoluminescent detectors. In this work, we have also demonstrated usefulness of a new system for positioning and removing samples in channel BH#3 of the IEA-R1 reactor at the Instituto de Pesquisas Energéticas e Nucleares (Brazil) without necessity of interrupting the reactor operation.