Lipopeptide; HSV-1; HSV-2
- Bacterial cell membrane (of avian pathogenic Escherichia coli, APEC) – disrupts membrane integrity to enhance the antibacterial activity of NSC277174 [1]
- Enveloped virus membrane (e.g., herpes simplex virus type 1, HSV-1; vesicular stomatitis virus, VSV) – disrupts viral envelope structure to inactivate viruses [3]
Surfactin's primary mechanism of action involves interaction with lipid membranes. It mediates the flux of mono- and divalent cations, including calcium, across lipid bilayer membranes. This membrane-disrupting activity contributes to its antimicrobial and hemolytic effects. Surfactin's ability to disrupt membrane integrity leads to leakage of cellular contents and cell death in susceptible microorganisms. The compound also exhibits antiviral activity against enveloped viruses, likely through disruption of the viral envelope. Surfactin can act as an antimicrobial adjuvant, enhancing the activity of other antimicrobial agents. Its membrane-active properties make it effective against a broad range of pathogens including Gram-positive and Gram-negative bacteria, fungi, and mycoplasma.

In vitro, surfactin can boost NSC277174's effectiveness against avian pathogenic Escherichia coli (APEC) using antimicrobial assays including fractional inhibitory concentration (FIC) and minimum inhibitory concentration (MIC). The minimum inhibitory concentrations of NSC277174 and surfactin for the APEC O78 strain are 1000 ug/ml and >1 mg/ml, respectively[1].

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- When combined with NSC277174, surfactin significantly sensitizes avian pathogenic Escherichia coli (APEC) to NSC277174 in vitro. The minimum inhibitory concentration (MIC) of NSC277174 against APEC is reduced by 4–8 folds in the presence of surfactin (at a concentration of 12.5 μg/mL). This sensitization effect is associated with surfactin-mediated disruption of the APEC cell membrane, as evidenced by increased membrane permeability (detected via fluorescent dye leakage assay) and reduced bacterial membrane potential (measured by flow cytometry) [1]
- Surfactin exhibits broad application potential in vitro, including as an emulsifier in bioremediation (enhancing the solubility and degradation of hydrophobic pollutants), a foaming agent in food processing, and a辅助 agent in pharmaceutical formulations (improving drug solubility and bioavailability). It also shows preliminary antibacterial activity against some Gram-positive bacteria (e.g., Staphylococcus aureus) in vitro, though with lower potency compared to its membrane-disrupting synergistic effects [2]
- Surfactin inactivates enveloped viruses in vitro, including herpes simplex virus type 1 (HSV-1), vesicular stomatitis virus (VSV), and influenza A virus. At a concentration of 50–100 μg/mL, surfactin reduces viral titer by >99% within 1 hour of incubation. The mechanism involves direct interaction with the viral envelope: surfactin disrupts the lipid bilayer of the envelope, leading to leakage of viral internal components (e.g., nucleic acids, proteins) and loss of viral infectivity. No inactivation effect on non-enveloped viruses (e.g., poliovirus) is observed [3]
In vitro, surfactin demonstrates broad-spectrum antimicrobial activity. It exhibits antibacterial activity against Gram-positive bacteria such as Staphylococcus aureus and antifungal activity against various fungi. Surfactin also shows antimycoplasmal and hemolytic effects. The compound has antiviral activity against a variety of enveloped viruses. Surfactin can increase the activity of other antimicrobial agents, such as NSC277174 against avian pathogenic Escherichia coli (APEC), as demonstrated by antimicrobial assays including fractional inhibitory concentration (FIC) and minimum inhibitory concentration (MIC) determinations. Its membrane-disrupting activity is responsible for its broad-spectrum antimicrobial effects. The compound's potency varies depending on the target organism and assay conditions.

Surfactin and NSC277174 work together to reduce the number of deaths and liver bacterial burdens in the chick infection model (E. coli inoculation) while also controlling the expression of inflammatory cytokines and other factors. When combined with NSC277174, surfactin can function as a new antibacterial adjuvant to prevent AEPC infection in chickens[1].

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- In a chick model of APEC infection, the combination of surfactin (2 mg/kg, intraperitoneal injection) and NSC277174 (5 mg/kg, intraperitoneal injection) significantly reduces APEC load in chick liver and spleen (by 2–3 logs compared to NSC277174 alone) and improves chick survival rate (from 40% in the NSC277174 alone group to 75% in the combination group). surfactin alone (2 mg/kg) shows no significant antibacterial effect on APEC in vivo but enhances the therapeutic efficacy of NSC277174 by promoting its penetration into bacterial cells via membrane disruption [1]
In vivo, surfactin has been studied for its antimicrobial and immunomodulatory effects. Its ability to act as an antimicrobial adjuvant suggests potential applications in combination therapy for infectious diseases. The compound's membrane-active properties and biosurfactant characteristics make it relevant for studies on biofilm disruption and infection control. However, detailed in vivo efficacy and safety data are limited, as surfactin is primarily used as a research tool and in industrial applications. Its hemolytic activity may limit systemic therapeutic applications but could be exploited for topical or localized treatments. Further research is needed to fully characterize its in vivo biological activity and therapeutic potential.

For in vitro biochemical assays, surfactin's antimicrobial activity is evaluated using standard susceptibility testing methods. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) are determined using broth microdilution or agar dilution methods against various bacterial and fungal strains. Hemolytic activity is assessed using red blood cell lysis assays. Membrane disruption is evaluated using liposome leakage assays or membrane potential-sensitive dyes. Antiviral activity is assessed using plaque reduction assays or viral titer reduction assays with enveloped viruses. Synergy studies with other antimicrobial agents are performed using checkerboard assays to calculate fractional inhibitory concentration indices. These assays help characterize surfactin's antimicrobial spectrum and mechanism of action.

- In a chick model of APEC infection, the combination of surfactin (2 mg/kg, intraperitoneal injection) and NSC277174 (5 mg/kg, intraperitoneal injection) significantly reduces APEC load in chick liver and spleen (by 2–3 logs compared to NSC277174 alone) and improves chick survival rate (from 40% in the NSC277174 alone group to 75% in the combination group). surfactin alone (2 mg/kg) shows no significant antibacterial effect on APEC in vivo but enhances the therapeutic efficacy of NSC277174 by promoting its penetration into bacterial cells via membrane disruption [1]
In vitro cellular assays for surfactin are performed using various cell types to assess its biological activities. Antimicrobial activity is tested against bacterial and fungal cultures. Cytotoxicity against mammalian cell lines is assessed using MTT or LDH release assays to evaluate selectivity. Hemolytic activity is measured using red blood cell suspensions. Antiviral activity is tested using virus-infected cell cultures. Membrane permeability is assessed using fluorescent dye uptake or release assays. Biofilm disruption is evaluated using crystal violet staining or confocal microscopy. The compound's effects on cell viability, proliferation, and membrane integrity are determined through dose-response studies. These cellular assays help validate surfactin's antimicrobial and membrane-active properties.

- One-day-old chicks were randomly divided into four groups (n=20 per group): normal control (no infection), infection control (APEC infection + saline), NSC277174 alone (APEC infection + 5 mg/kg NSC277174, intraperitoneal injection), and surfactin + NSC277174 (APEC infection + 2 mg/kg surfactin + 5 mg/kg NSC277174, intraperitoneal injection). Chicks were infected with APEC (10^8 CFU/chick) via intraperitoneal injection 24 hours before drug administration. Drugs were dissolved in sterile saline and administered once daily for 3 consecutive days. Chick survival was recorded daily for 7 days. On day 7, liver and spleen tissues were collected, homogenized, and plated on LB agar to count APEC colonies (CFU/g tissue) [1]
In vivo animal experiments with surfactin are limited, as the compound is primarily used as a research tool and industrial biosurfactant. If used in animal studies, typical approaches would involve administration via topical application, oral gavage, or injection. Infection models using bacterial or fungal pathogens could be used to assess antimicrobial efficacy. Wound healing or biofilm infection models could evaluate surfactin's potential for infection control. Toxicity and tolerability studies would assess the compound's safety profile. Endpoint analyses would include microbial load quantification, tissue histopathology, and assessment of inflammatory markers. Researchers should consult the primary literature for any available in vivo data on surfactin.

Pharmacokinetic properties of surfactin are not extensively documented. As a cyclic lipopeptide with high molecular weight and amphiphilic properties, surfactin is expected to have limited oral bioavailability and to primarily exert its effects at the site of application. The compound's surface-active properties may affect its distribution and interaction with biological membranes. For systemic administration, surfactin would likely be subject to rapid clearance and potential toxicity due to its hemolytic activity. Its use as a biosurfactant and antimicrobial adjuvant is primarily in topical, agricultural, or industrial applications rather than systemic therapeutic use. Detailed PK parameters are not available in the literature.

In vitro cytotoxicity assays on Vero cells (mammalian cells) showed that surfactant was low in cytotoxicity: 50% cytotoxic concentration (CC50) > 200 μg/mL, which is 2–4 times higher than the concentration required for virus inactivation (50–100 μg/mL) [3]
- In chick models, intraperitoneal injection of surfactant (2 mg/kg) showed no significant toxicity: no chick mortality, weight loss, or histopathological changes (e.g., liver or kidney damage) were observed in the surfactant-treated group compared with the normal control group [1]
- In vitro experiments showed that surfactant was low in toxicity to aquatic organisms (e.g., Daphnia magna) and plants (e.g., wheat seedlings), with a 48-hour LC50 > 100. For Daphnia magna, a concentration of μg/mL indicated its potential for environmental safety in bioremediation applications [2]
The toxicological profile of surfactin is characterized by its hemolytic activity. As a membrane-active compound, surfactin can cause lysis of red blood cells at certain concentrations, which limits its systemic therapeutic applications. The compound's cytotoxicity against mammalian cells has been assessed in vitro, and its safety profile depends on the concentration and route of exposure. Surfactin is generally considered to have moderate toxicity, with the potential for irritation and membrane damage. Comprehensive toxicity studies including acute, subchronic, and chronic toxicity assessments are limited. The compound is intended for research use only and not for human therapeutic applications without appropriate safety evaluation. Researchers should follow standard laboratory safety practices when handling surfactin.

[1]. Sensitization of avian pathogenic Escherichia coli to NSC277174 in vitro and in vivo in the presence of surfactin. PLoS One. 2019 Sep 12;14(9):e0222413.

[2]. Applications of a lipopeptide biosurfactant, surfactin, produced by microorganisms. Biochemical Engineering Journal. 103 (2015) 158-169.

[3]. Mechanism of inactivation of enveloped viruses by the biosurfactant surfactin from Bacillus subtilis. Biologicals. 1997 Sep;25(3):289-97.

Surfactant C is a cyclic condensate with the chemical formula N-[(3R)-3-hydroxy-13-methyltetradecanoyl]-L-α-glutamyl-L-leucyl-D-leucyl-L-valine-L-α-aspartyl-D-leucyl-L-leucine, wherein the C-terminal carboxyl group condenses with an alcohol hydroxyl group to form a lactone. It possesses various activities including antibacterial, antifungal, antiviral, surfactant, metabolite, antitumor, and platelet aggregation inhibitor activities. It is a cyclic condensate, lipopeptide antibiotic, and macrolide. Surfactant has been reported to exist in Bacillus subtilis, Bacillus mojavenius, and Bacillus thuringiensis, and relevant data are available. See also: Surfactant peptide (note moved to). Surfactant is a lipopeptide biosurfactant mainly produced by Bacillus subtilis strains. It consists of a cyclic peptide ring (7 amino acids) and a fatty acid chain (13-15 carbon atoms), which gives it amphiphilicity (having both hydrophilic and hydrophobic regions) – key to its ability to disrupt cell membrane activity [2, 3]
- The synergistic effect of surfactant with NSC277174 provides a strategy for addressing antibiotic resistance in avian Escherichia coli (APEC, a major pathogen causing avian colibacillosis). By reducing the required dose of NSC277174, surfactant may minimize the risk of antibiotic residues in poultry products [1]
- Surfactant has envelope-specific antiviral activity, making it a potential candidate for developing broad-spectrum antiviral drugs against enveloped viruses such as influenza and coronaviruses, especially in cases requiring surface disinfection or topical application (e.g., nasal sprays) [3]
Surfactin is a versatile biosurfactant with diverse applications in pharmaceutical, agricultural, and industrial research. Its antimicrobial adjuvant properties make it valuable for studying combination therapies and overcoming antimicrobial resistance. The compound's membrane-disrupting activity provides opportunities for investigating membrane biology and developing novel antimicrobial strategies. Surfactin's antiviral activity against enveloped viruses makes it relevant for virology research. In agriculture, surfactin is studied for its potential as a biopesticide and plant protection agent. Its biosurfactant properties are also exploited in industrial applications including enhanced oil recovery, bioremediation, and food preservation. The compound's cyclic lipopeptide structure makes it an interesting model for studying structure-activity relationships in membrane-active peptides.

1025.04 (average)

1035.683

252023-70-4

302933-83-1 (Sodium Surfactin); 24730-31-2; 252023-70-4

443592

White to off-white solid powder

8.8

9

13

24

73

1800

8

O1C([C@H](CC(C)C)NC([C@@H](CC(C)C)NC([C@H](CC(=O)O)NC([C@H](C(C)C)NC([C@@H](CC(C)C)NC([C@H](CC(C)C)NC([C@H](CCC(=O)O)NC(C[C@H]1CCCCCCCCCC(C)C)=O)=O)=O)=O)=O)=O)=O)=O

NJGWOFRZMQRKHT-WGVNQGGSSA-N

InChI=1S/C53H93N7O13/c1-30(2)20-18-16-14-13-15-17-19-21-36-28-43(61)54-37(22-23-44(62)63)47(66)55-38(24-31(3)4)48(67)57-40(26-33(7)8)51(70)60-46(35(11)12)52(71)58-41(29-45(64)65)50(69)56-39(25-32(5)6)49(68)59-42(27-34(9)10)53(72)73-36/h30-42,46H,13-29H2,1-12H3,(H,54,61)(H,55,66)(H,56,69)(H,57,67)(H,58,71)(H,59,68)(H,60,70)(H,62,63)(H,64,65)/t36-,37+,38+,39-,40-,41+,42+,46+/m1/s1

3-[(3S,6R,9S,12S,15R,18S,21S,25R)-9-(carboxymethyl)-3,6,15,18-tetrakis(2-methylpropyl)-25-(10-methylundecyl)-2,5,8,11,14,17,20,23-octaoxo-12-propan-2-yl-1-oxa-4,7,10,13,16,19,22-heptazacyclopentacos-21-yl]propanoic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : 50 mg/mL H2O : 31.25 mg/mL

Solubility in Formulation 1: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (Infinity mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 110 mg/mL (Infinity mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)