Anti-Microbial Peptides from Medicinal Plants as an Alternative against Multi Drug Resistance

Review Article

J Bacteriol Mycol. 2022; 9(2): 1199.

Anti-Microbial Peptides from Medicinal Plants as an Alternative against Multi Drug Resistance

Singh A¹, Pamidimarri SDVN² and Chauhan S¹*

1Amity Institute of Biotechnology, Amity University Chhattisgarh, Raipur, Chhattisgarh 493225, India

2Discipline of Industrial Biotechnology, Gujrat Biotechnology University Gandhinagar, Gujarat, India

*Corresponding author: Sushma Chauhan, Amity Institute of Biotechnology, Amity University Chhattisgarh, Raipur, Chhattisgarh 493225, India

Received: September 23, 2022; Accepted: November 01, 2022; Published: November 08, 2022


From its discovery to today, antibiotics have revolutionized medicine, and various antibiotics have been studied, discovered and put to significant application and it continues to be helpful in controlling infections. Nonetheless over application of these antibiotics have given rise to Antibiotic Resistance (AR) and Multidrug Resistant pathogens (MDR) against the various antibiotic’s agents. Anti-microbial peptides are being explored as an alternative against the prevalent issue of MDR and AR. Anti-microbial peptides are the part of host’s first line of defense mechanism of innate immune response, are small peptides its molecular weight is 2-10kDa, it holds amphiphillic properties, and is usually positively charged at neutral pH value. The advantages posed by anti-microbial peptides are many like broad antimicrobial spectrum, rapid action, and lower risk of resistance, low toxicity and high selectivity. It poses many therapeutic like anti-cancerous, anti-inflammatory, anti-bacterial, anti-fungal, anti-viral, and immunomodulator properties as well. Plants are good source of antimicrobial peptides. A variety of applications can be achieved with plant derived antimicrobial peptides, including antibacterial, insecticide, and infection control, including the control of cellular infection by viruses. AMPs exist in different molecular forms like Cyclotides, cyclic cysteine knot, defensin, thionin, snakin- Like, hevein-like, knottin like peptides etc. It is expected that anti-microbial peptides will have a positive impact on medicine, food, industries as antifouling agents and agriculture. The major objective of this review articleis to explore and identify important antimicrobial peptides in medicinal plants like Ocimum sanctum and Santalum album.

Keywords: Anti-microbial peptides; Multi-drug resistance; Ocimum sanctum; Santalum album


AMPs: Antimicrobial Peptide; MOA: Mechanism of Action; MDR: Multi-Drug Resistance; AR: Antibiotics Resistance; MRSA: Methicillin- Resistant Staphylococcus Aureus


The use of medicinal plants dates back to Vedic period (3500– 1600 B.C) when books on Ayurvedic medicine were written and the use and practice of medicinal plant was described which formed the basis of medical sciences [1]. Over 90% of traditional medicine remedies contain medicinal plants and continues to be used to aid certain diseases and enhance immune system [2]. Tulsi (Ocimum sanctum) is an aromatic herb which has been very widely used for centuries due to its healing properties and is known as the ‘Queen of herbs’ [3]. It belongs to the Lamiaceae family and is usually found in the tropical and subtropical regions [4]. It is an erect, sub shrub with purple and green leaves and possesses definite therapeutic properties [1]. There are certain studies that pointed out towards the antimicrobial activity of tulsi which exhibits anti-bacterial, anti-fungal, anti-viral activity, and anti-cancer activity [5], O. sanctum L. essential oil is shown to have antibacterial activity against several pathogenic microorganism such as Staphylococcus aureus, Bacillus pumilus and Pseudomonas aeruginosa [6]. The leaves of tulsi are also shown to have anti-fungal properties against the Aspergillus species. Santalum album on the other hand is an aromatic wood, which has been esteemed since primeval times commonly known as Sandalwood; it belongs to the Santalaceae family and is usually found in the dry regions of India and in China, Indonesia and the Philippines. It is an evergreen, semi parasitic plant, the mostly used part of sandalwood is heartwood which appears yellowish brown when fresh and gradually turn dark in color upon exposure, the heartwood is scented and possess diuretic, disinfectant anti-pyretic haemostatic and many such properties [3]. The leaf extract of S. album is shown to have anti-microbial activity against E.coli, Staphylococcus aureus and Pseudomonas [7], its aqueous extract is shown to have strongest inhibition against S. aureus [8]. Now with the help of advancement in genome wide research and whole genome sequence available in public database like NCBI, the scientific and actual secret behind the numerous advance properties of this medicinal plant can be explore. Moreover, the gene or cluster of gene can be identified which decode the full or partial peptide which own the AMPs activity. Anti-microbial peptides are part of host’s first line of defense mechanism of innate immune response, they are generally small peptides with molecular weight is upto 2-10kDa. These tiny peptides hold amphiphillic properties and is usually positively charged at neutral pH value. These are small proteins or part of protein with potent anti-bacterial, anti-viral and anti-fungal activity and are ubiquitous in nature [9]. AMPs have a wide range of activity, including the ability to kill bacteria, fungus, yeasts, and cancer cells, viruses either directly or indirectly. It is also known as host defense peptides because of its immune modulatory activities which make it unique in nature. These peptides are mostly used by plants and insects as an antibiotic to lookout against potentially dangerous microorganisms [10]. The plant kingdom is adapted to hold diverse types of peptides to protect against microbes since they are short of specialized immune system like animals [11]. Anti-microbial peptides are quite diversified and are classified on the basis of; source, activity, structural characteristics and amino acid rich species [12]. There are several features of AMPs that makes it important like AMPs target the lipopolysaccharide layer of the microorganism unlike the antibiotics which targets specific cellular activities [13], and second is its rapid killing effect [14]. AMPs have been studied as an alternative microbial agent as its mode of action of killing bacteria is discrete than the Mechanism of Action (MOA) of antibiotics [15]. Its mode of action to kill the pathogen or bug are usually depends upon their interaction with bacterial cell membranes or cell walls [10]. They kill bacteria using two extensive mechanisms of action; first mechanism is membrane disruption induced by AMPs which leads to cell lysis and death [16]. The second mechanism of APMs is through entering the cell without any membrane disruption and binding to nucleic acids or intracellular proteins to inhibit all the essential intracellular functions [17]. AMPs enter into the well-defined membrane bilayers and form pores in different way like ‘barrel-stave’, ‘carpet’ or ‘toroidal-pore’ mechanisms [16]. AMPs can be employed in various areas like medicine as they can recruit cells, promote wound healing, stimulate the proliferation of cells, kills cancer cells, alter gene expression, as well as regulate pro-inflammatory reactions [18]. In food industry, as it inhibits bacteria and fungi and many AMPs are also resistant to high temperatures, alkalis and acids and can be hydrolyzed byproteases easily and therefore it is a potential alternative as food preservatives [19], in aquaculture, poultry and animal husbandry to enhance production performance [20,21]. Also, the AMPs not only applicable in above-mentioned sector but also, they are having potential application in agriculture industry as AMPs have the potential to control the pathogenic infection of plants by bacteria and fungi. Due to its physio-chemical properties, activity towards wide spectrum of bacteria and different mode of action from the current in use antibiotics it is a striking alternative to traditional antibiotics [22].

History of Antibiotics

Discovery of antibiotics certainly revolutionized the whole world by significantly contributing to controlling infections by either killing the bacteria or inhibiting its growth. The antibiotic era started with the very first antibiotic ‘Penicillin’ in 1928 which led to the production and commercialization of various other antibiotics. Though penicillin was not the first antibiotic, it was first Salvarsan developed in 1909-10 by Paul Ehlrich and Sahachiro Hata to treat syphilis [23], which was later on replaced by penicillin in the 1940s. Several new antibiotics have been discovered and use, important types of antibiotics which still playing remarkable role include penicillin, tetracycline, cephalosporin, quinolones, linomycins, macrolides, sulfonamides, glycopeptides, aminoglycosides, and carbapenems. It has been widely used by the health practitioners to treat and control infections and also has been used in agriculture, aquaculture and horticulture [24] (Figure 1).