Bergenia ciliata as antibacterial agent

The search for alternatives to combat antibiotics has been increased due to the upsurge in cases of antibiotic-resistant pathogens that has become a global phenomenon which threatens the human health. Medicinal plants provide multiple health benefits because these plants contain bioactive phytochemicals that are used in medicines as alternatives to various ailments of human beings. Bergenia ciliata is a perennial herb belongs to the family Saxifragaceae that consists of about 30 genera and 580 species worldwide. It has large, evergreen and leathery leaves with the pink to dark purple flowers and has various traditional and modern medical uses. This plant is considered is one of the most effective antibacterial agents. The present review emphasizes the antibacterial potential of Bergenia ciliata by compiling various researches and fragmented information. The most important phytochemicals derived from Bergenia ciliata launched on the pharmaceutical market are also discussed. This attempt will help the researchers to develop and synthesize new antibacterial drugs from Bergenia ciliata against drug-resistive pathogens.


Introduction
The interrelation of human beings with their surrounding herbs and medicinal plants draws its roots to the ancient civilizations [1].Approximately 270,000 plant species are discovered till present time, while the existence of 400,000 plant species is possible in mother earth [2,3].Plants are nature's gift to the humans as they are the main source of many bioactive substances and modern as well as traditional drugs [4].Approximately 35,000 to 70,000 plant species are used for medicines in the world and about 80 percent of world's population used medicinal plants for the treatment of various diseases i.e. arthritis, diabetes, eye infection, loss of hair, loose motion, skin disease, abortion, kidney stone, cough, hyper tension, stomach diseases and loss of alertness etc. [5].Plants are the main source of medicinal compounds.These medicinal compounds, which provide a great help in the discovery of new medicines, isolated from plants are being studied by many researchers worldwide for their various medicinal activities [6].
Generally there are about 58 different phytochemicals present in Bergenia ciliata species of which some are categorized into 11 categories viz; alcohols, fatty acids, phenols, carboxylic acids, terpenoids, flavonoids, glycosides, nitro compounds, sterol, cinnamic acid and volatile organic compounds [10].
The innovation of antibiotics is the most important discovery in the 20 th century which has helped the human being in his everlasting battle against pathogens.But some species of pathogens had developed a significant resistance against the discovered antibiotics [14].An utmost focus of contemporary medicine is the search for new strategies and substances to combat infectious diseases.This problem is very staid because many bacteria are very resistant to antibacterial drugs and leads to difficulty in treatment of infectious diseases.For example, Staphylococcus aureus, a Gram-positive, round-shaped bacterium, is highly resistant to antibiotics [15].Such a resistance of microorganisms towards antibiotics causes approximately 25, 000 deaths per year in the European Union and about 23, 000 deaths in the USA.This problem is approaching towards more dangerous levels due to the scarcity of development of new antibiotics as over the past twenty five years only two classes of antibiotics viz; lipopeptides and oxazolidinones have been developed [16,17].The only solution for this problem is the synthesis and discoveries of new antibacterial and other compounds to combat the resistance of pathogens against the antibiotics.Therefore, it is essential to develop and synthesis new antibiotics to control the resistance of pathogens.Due to the great importance of antibacterial drugs developed and synthesized from plants we gather the utmost fragmented literature about antibacterial activities of Bergenia ciliata and its important phytochemicals.Moreover, this review will help the researchers across the world to develop new antibacterial drugs from Bergenia ciliata against the resistive pathogens.

Bergenia ciliata in traditional medicines
Traditional medicinal system has been utilized since prehistoric times and draws its roots to ancient civilization.About 2500 plant species have medicinal value and about 6000 plants have been recognized to be used in traditional, folk and herbal medicine [18].Bergenia ciliata is an attractive medicinal plant which attracts many researchers due to various medicinal activities.It is also used in traditional medicines for the treatment of many diseases i.e. skin diseases, muscular/skeletal disorders, pulmonary infections, gastrointestinal infections, fever, eye diseases ,worm infection , diarrhea, respiratory diseases, renal disorders, fever , oral infections, cancer, and gynecological disorders (Figure 1) [7].Traditional healers used it mainly in the form of powder.Juice of dried rhizome of Bergenia ciliata in combination with honey has been used by post-partum women against the gastrointestinal disorders.Its rhizome has also been used by adults as an anti-helimintic.Boiled roots of Bergenia ciliata in combination with salt have been reported to be used for the cure of asthma.Its use for the treatment and prevention of piles and cancer is also reported [7,19,20].

Phytochemistry of Bergenia ciliata
Bergenia ciliata is an important medicinal herbal plant that contains many important bioactive compounds.Many researchers have evaluated various phytochemicals from Bergenia ciliata (Figure 2; Figure 3).Generally there are about 58 phytochemicals present in Bergenia ciliata species of which 48 volatile organic compounds are categorized into 11 categories viz; alcohols, fatty acids, phenols, carboxylic acids, terpenoids, flavonoids, glycosides, nitro compounds, sterol, cinnamic acid and volatile organic compounds [10].Some of the important classes of compounds along with their IUPAC names and general formula isolated from Bergenia ciliata are given in Table 1.

Bergenia ciliata as antibacterial agent
The renewed interest of researchers in medicinal plants allowed them to investigate medicinal plants, such as Bergenia ciliata, and search new strategies and substances to combat infectious diseases.Several pharmacological studies reported that Bergenia ciliata is a potent antibacterial agent (Table 2).In present study we have reviewed different extracts of Bergenia ciliata that can be used against pathogenic bacteria.The antibacterial activities of three medicinal plants including Bergenia ciliata have been investigated.The acetone extracts of the plants showed remarkable anti-inhibitory effect against three pathogens, namely Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa [30].It was published that rhizome extracts (in methanol, ethanol, water and n-hexane) of Bergenia ciliata showed significant antibacterial potential against four bacterial strains; Klebsiella pneumonia, Staphylococcus auereus, Bacillus subtilis and Escherichia coli.Among all the extracts the methanolic extract showed greater inhibitory potential (12.9±0.5 to 11.8±0.7mm)while the lowest inhibition was showed by aqueous fraction (4.5±0.3 to 3.5±0.1mm)[32].Another study reported that ethanolic rhizome extracts of Bergenia ciliata showed remarkable antibacterial activities against selected pathogens Salmonella typhimurium (inhibition zone 12±1.0mm) and Escherichia coli (inhibition zone 11.33±0.57mm)[33].The ethanolic, chloroform, butanolic, hexane, ethyl acetate and aqueous roots and leaves extracts of Bergenia ciliata were evaluated for their antibacterial inhibitory activity against Gram positive and Gram negative strains viz; Staphylococcus auereus, Bacillus subtilis, micrococcus and Bacillus megalerium.It was observed from the results that root extracts of Bergenia ciliata have higher antibacterial activities as compared to the leaves extracts [34].The antibacterial activities of callus extracts of Bergenia ciliata were determined against selected pathogens viz; Pseudomonas aeruginosa, Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas aeruginosa, Staphylococcus aureus and Pseudomonas aeruginosa [35].The methanol, ethyl acetate and hexane extracts of Bergenia ciliata were evaluated against the selected bacterial strains including Nocardia tenerifensis, Bacillus megaterium and Bacillus subtilis.Among all the extracts the methanolic extract was found to have better antibacterial potential [20].The antibacterial potential of the crude extract of Bergenia ciliata was determined against six bacterial strains including Bordetella bronchiseptica, Salmonella Setubal, Escherichia coli, Micrococcus luteus, Staphylococcus aureus and Salmonella typhimurium.The results showed that the crude extract significantly inhibited all the selected pathogens [36].In vitro ethanolic , hexane, distilled water and butanolic extracts of Bergenia ciliata also showed significantly antibacterial activities against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus faecalis bacteria [37].Leaves extracts of Bergenia ciliata showed significant antibacterial potential against Staphylococcus aureus and Bacillus megaterium with an inhibition zone of 8-12 mm and 10-20 mm respectively [38].

Conclusion
The present study gathers the fragmented literature about the antibacterial potential of Bergenia ciliata.The phytochemicals present in of Bergenia ciliata exhibit various biological activities including antibacterial, antioxidants, antifungal, antihaemolytic and cytotoxic.This mini-review would be beneficial for researchers in future to study the medicinally important constituents of Bergenia ciliata to develop new drugs that can be used to combat the antibioticresistant pathogens.Based on current review, Bergenia ciliata is considered is one of the most important antibacterial agent which attributed to its phytochemical constituents but some of the constituents of Bergenia ciliata has adverse effects on human health.Therefore, in-depth and intensive studies are required in order to isolate the antibacterial molecules and evaluate the safety, dosage and possible side effects.

Table 1
Some important phytochemicals isolated from Bergenia ciliata.

Table 2
Antibacterial activities of Bergenia ciliata.