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Green soap formulation: an insight into the optimization of preparations and antifungal action

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Abstract and Figures

Ultrasound-assisted extract of Acalypha indica was used to prepare the green soap formulation. Previously, D-optimal mixture design was used to optimize the mixture of oil components including coconut oil (A, 34–56%), soybean oil (B, 19–31%), castor oil (C, 14–23%), sunflower oil (D, 4–6%), and olive oil (E, 5–9%). Linear regression models were proposed to predict the responses, i.e., hardness (Y1), iodine (Y2), and iodine number saponification (INS) (Y3), and validated with a high degree of statistical accuracy (Fcal > Ftab; df = 4, p < 0.0001; R² > 0.9950). Optimization results revealed that the formulation containing 44.57% A, 23.62% B, 17.44% C, 5.37% D, and 9.0% E would yield 41 Y1, 62 Y2, and 159 Y3. The chemical properties of the optimized soap formulation were quite comparable concerning the standard soap specifications (IS13498). Further, this formulation was supplemented with Acalypha indica extract to prepare the green soap, and its antifungal activity was determined using the agar dilution method. Graphical abstract
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Green soap formulation: an insight into the optimization
of preparations and antifungal action
Arunachalam Thirunavukkarasu
&Rajarathinam Nithya
&Raja Sivashankar
&Arunachalam Bose Sathya
Selvasembian Rangabhashiyam
&Sivanantham Arul Pasupathi
&Murugan Prakash
&Mayilvahanan Nishanth
Received: 6 August 2020 /Revised: 25 September 2020 /Accepted: 16 October 2020
#Springer-Verlag GmbH Germany, part of Springer Nature 2020
Ultrasound-assisted extract of Acalypha indica was used to prepare the green soap formulation. Previously, D-optimal mixture
design was used to optimize the mixture of oil components including coconut oil (A, 3456%), soybean oil (B, 1931%), castor
oil (C, 1423%), sunflower oil (D, 46%), and olive oil (E, 59%). Linear regression models were proposed to predict the
responses, i.e., hardness (Y
), iodine (Y
), and iodine number saponification (INS) (Y
), and validated with a high degree of
statistical accuracy (F
> 0.9950). Optimization results revealed that the formulation containing
44.57% A, 23.62% B, 17.44% C, 5.37% D, and 9.0% E would yield 41 Y
, and 159 Y
. The chemical properties of the
optimized soap formulation were quite comparable concerning the standard soap specifications (IS13498). Further, this formu-
lation was supplemented with Acalypha indica extract to prepare the green soap, and its antifungal activity was determined using
the agar dilution method.
Keywords Green soap formulation .Acalypha indica .D-optimal mixture design .Antifungal activity
1 Introduction
Cosmetics are the range of products that are used to enhance the
personal appearance or the physical appeal of an individual [1].
Mostly, these cosmetics are categorized into skincare, hair care,
perfumes, deodorants, personal care, and oral cosmetics. In the
modern era, the use of these items is inevitable in the routine
life of every individual, and hence, the markets for such cos-
metic products are in the exponential phase. According to the
recent report, the global market value of cosmetics was about
507.8 billion US dollars in 2018 and it is expected to increase to
about 758.4 billion US dollars by 2025 [2]. Among them,
skincare tops the list contributing to about 39% of the total
market size [3]. However, the various chemicals used in the
preparation of skincare formulations might cause ill effects
ranging from mild allergic reactions to carcinogenicity [4].
For instance, the use of debenzoylmethanes, paraaminobenzoic
acid (PABA), and cinnamates in sun-screen products are capa-
ble of causing photoallergic dermatitis [5]. Likewise, the use of
butylated hydroxyl anisole (BHA) and butylated hydroxyl tol-
uene (BHT) in moisturizers and lipsticks were identified as the
potent carcinogen and endocrine disruptors. Further, FDA
banned the use of antibacterial soap formulations having the
list of 19 different chemicals (Table 1) as these chemicals were
failed to prove them as Generally Recognized As Safe and
Effective (GRAS/GRAE) [6]. Hence, the formulation scientists
in the cosmetics fields are highly focusing on developing a
wide range of green-based products with no or minimal use
of these hazardous chemicals.
Soaps are one of the skincare products that can be defined
as the cleansing agent produced by the saponification reaction
of oils and fatty acids in presence of sodium or potassium
hydroxide (lye solution) [7]. Soaps are amphipathic in nature,
consisting of polar ionic hydrophilic head molecules and non-
polar hydrophobic tail molecules. In dissolution with water,
these soap molecules get arranged themselves as spherical
aggregates called micelles. These micelles have the water-
*Arunachalam Thirunavukkarasu
Department of Industrial Biotechnology, Government College of
Technology, Coimbatore, India
Department of Chemical Engineering, Hindustan Institute of
Technology and Science, Chennai, India
Department of Biotechnology, Aarupadai Veedu Institute of
Technology, Chennai, India
School of Chemical and Biotechnology, SASTRA University,
Thanjavur, India
/ Published online: 21 October 2020
Biomass Conversion and Biorefinery (2023) 13:299–310
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... Owing to this fact, the present study is intended to find the optimal combination(s) of the substrate with the use of prediction-based optimality designs such as G-optimal, D-optimal, I-optimal, etc. [14,38,53]. In recent years, scholarly articles were reported on the use of such statistical-based optimal mixture designs in a wide variety of applications such as adsorption, biodiesel production, green soap formulation, etc. [30,31,34,44,45,[51][52][53]55]. Of them, the D-optimal mixture design is the most preferred to minimize the mean/average prediction variance over the least experimental designs. ...
... A multi-layered feed-forward ANN with back-propagation (BP) algorithm was used in the present study to model the vermicomposting process. These multi-layered structure feed-forward non-linear regression models can be analyzed well with the use of sophisticated statistical tools like ANN [9,30,44,51,53,55]. BP algorithm reduces errors by tracing the source of the error linkages between inputs and outputs, which allows for continuous learning and improves the network's performance [31,58]. ...
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In the present study, fortified cow dung substrates in different proportions were employed to convert them into stable and mature vermicompost using the earthworm, Eisenia fetida. With the use of the I-optimal matrix of the mixture design, 94.46% of cow dung fortified with 5.54% of Calotropis gigantea was found to be optimal. The vermicompost derived from this optimal substrate mixture showed a carbon–nitrogen ratio (C/N) of 13.76, carbon dioxide evolution (CO2) of 0.49% with a high germination index (G.I) of 97.38%. Further, the process of composting was modeled with the use of the back propagation algorithm of artificial neural network (ANN) and the developed model was found to be statistically significant with a high correlation coefficient (R > 0.99) and minimum mean square error (MSE < 0.5). Graphical abstract
... In the soap production process, various mixtures of oils are used, and in some cases improper combinations of the oils may not undergo the saponification action and remain in the soap as unreacted fatty acids, which causes skin irritation and bleaching effects. Hence, the appropriate selection of the right proportions of the oil mixtures is highly challenging in the product development phase [4]. ...
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In this work, preparation of fragrant soap was performed by mixing rose, mint, lemon, or orange essential oil with “Al-Jouf” olive oil (a well-known olive oil brand) in ethanolic-aqueous solution during the saponification process. To avoid volatilization of the essential oils, saponification was conducted in reflux system at 95oC for 1h. The resulting soap was then precipitated using different volumes of 30% sodium chloride aqueous solution, filtered, poured into silicon molds, and left to dry at room temperature till constant weight. The resulting soap was evaluated by 1) reaction efficiency, 2) UV-Visible spectrophotometer, 3) Fourier-Transform Infrared Spectroscopy, and 4) antibacterial efficacy. Results showed that increasing sodium chloride concentration highly increases the reaction efficiency. Colony counting method showed that all soap samples prepared using olive oil/essential oil mixture acquired good antibacterial properties, whereas antibacterial efficacy of soap prepared from olive oil only acquired up to 95.4% reduction of Staphylococcus aureus colonies and up to 89.5% reduction of Escherichia coli colonies.
... It is a subclass of response surface methodology (RSM). It has found successful applications in the formulation of cosmetics, 15 paints and coatings, 16,17 soaps and shampoos, 18,19 pharmaceutical products, 20 foods and beverages 21,22 as well as polymer composites. 12,23 In this study, the mixture design of experiments was utilized to design an optimum formulation for the oat-hull reinforced polypropylene composite for automotive applications. ...
Natural fiber-reinforced composites (NFRC) are cheaper and more eco-friendly alternatives compared to synthetic composites for automotive applications. As there is limited understanding about the balance of different physical properties in NFRC, optimizing these properties is an important consideration for a more widespread application of NFRC. The goal of this research was to statistically develop an optimum formulation for oat-hull-reinforced polypropylene composite. Mechanical properties of the composites were first experimentally measured. Then, the mixture design experiment approach was utilized to generate response models for different properties and diagnostic tools were utilized to validate the models. In addition to optimizing the desired material properties, the overall cost of the composite was minimized, which adds novelty to the work.
... Various nature-based compounds, such as vegetable oils and plant and fruit extracts, have been reported to have antimicrobial, antifungal, and antioxidants properties (Masdar et al., 2020;Thirunavukkarasu et al., 2020;Ameh et al., 2013). These natural compounds are readily biodegradable and do not produce any additional dangerous waste. ...
A year into the coronavirus disease 2019 pandemic, the role of washing hands with soap and hand disinfectants is unavoidable as a primary way to control the infection spread in communities and healthcare facilities. The extraordinary surge in demand for handwashing products has led to environmental concerns. Since soaps are complex mixtures of toxic and persistent active ingredients, the prudent option is to promote eco-friendly replacements for the current products. On the other hand, with the increase in soap packaging waste production, soap packaging waste management and recycling become essential to reduce environmental impact. This systematic review aimed to collect some recent methods for identifying biodegradable and sustainable raw materials to produce and package cleaning agents, especially soap.
In the present study, a novel plant-mediated approach was reported to synthesize a bimetallic oxide (BMO, gCaO-CeO2) catalyst from waste egg shells. Previously, an equi-molar mixture of cerium nitrate and shell recovered calcium nitrate was considered as precursor for Prosopis juliflora mediated green synthesis. The prepared gCaO-CeO2 was characterized by means of FT-IR, TG/DTA, XRD and surface area analyzer. X-ray diffraction results showed that the gCaO-CeO2 is thermally stable even after the calcination process at 800 °C as the peaks for the cubic fluorite of cerium oxide (CEO) and cubic nature of calcium oxide (CO) were observed intact. Batch transesterification of karanja oil showed an improved catalytic activity for gCaO-CeO2 than monometallic oxides due to the increased basicity of the catalysts with the reduced temperature maxima. The highest fatty acid ethyl ester (FAEE) content of 96.17 % was attained for 6:1 mol ratio of ethanol-karanja oil over 4% (weight basis) of gCaO-CeO2 catalyst at 65 °C in 5 h. Further, the physico-chemical parameters of the transesterified products were found consistent with ASTM D6751 biodiesel standards. The study also reported the potential reuse of gCaO-CeO2 catalyst upto 6 operations with no appreciable loss in catalytic activity during transesterification.
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The word ‘cosmetics’ is taken from a Greek word “kosmeticos” which means to adorn. Since early days materials used for beautification or improvement of appearance comes under the category of cosmetics. People want to look beautiful and the concept of cosmetics is as old as mankind and civilization. The urge to beautify one’s own body and look beautiful has been an urge in the human race since the tribal days. Assorted beauty products such as skincare products, hair products, fragrances, oral hygiene, and nail products, which may contain toxic chemicals that can be harmful to health are used especially by women. Since long time cosmetics have been known to enhance the appearance of the human body. In a society obsessed with beauty, people are lured to fake their appearance as a cure for their insecurities. The estimated value of cosmetic industry today is around 20 billion dollar globally. As a consumer, we are constantly attracted in using beauty and personal care products. But these products, which are supposed to make us feel healthy and look beautiful, have a deep dark side. Various toxic ingredients and hazardous chemicals used in cosmetics are incorporated in beyond acceptable limits. These chemicals may cause serious ill effects on skin and may also enter skin and other organs causing carcinogenicity. Cosmetics have not only seeped into the fashion world but are also playing a prominent role in one’s day-to-day life. Thus, it becomes a necessity to make people aware of various harmful effects of cosmetics and chemicals used in cosmetics.
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Anti-microbial and anti-fungal activity of different solvent extracts of Acalypha indica (Euphorbeace family) was tested against bacterial pathogens (Pseudomonasaeruginosa, E.Coli, KlebsiellaPneumonia and Staphylococcus aureus) and fungal strains (Candida albicans, Aspergillus niger, Candida tropicalis andCandida kefyr) using the Agar Well diffusion method . It was observed that all the extracts showed positive activity) against bacteria and fungi. Ethanolic extract of Acalypha indica showed more potency against Staphylococcus aureus with an inhibition zone of12.46 (mm) and Methanolic extract exhibited higher activity against E.coli with an inhibition zone of11.26 (mm). Ethanolic extract of Acalypha indica showed prominent antifungal activity against candida albicans with an inhibition diameter of 12.53 (mm) and Aspergillus niger with a diameter of 9.21 (mm) when compared to other solvent extracts. Erythromycin and Ketoconazole were used as positive standards for antimicrobial and anti fungal experiments. In the present study, Ethanol extract showed a varying degree of inhibition to the growth of tested organisms compared to Methanol, Acetone and Chloroform against Bacteria and Fungi. The results confirmed the presence of antibacterial and antifungal compounds in shade dried extracts of Acalypha indica against human pathogenic organisms.
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Cerium oxide nanoparticles (CONPs) were prepared using ultrasound assisted leaf extract of Prosopis juliflora acting as a reducing as well as stabilizing agent. The synthesized CONPs were characterized by ultraviolet-visible absorption spectroscopy (UV-Vis), particle size analyzer (PSA), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). From the UV-Vis analysis, the optical band gap of the prepared CONPs (Eg = 3.62 eV) was slightly increased as compared to the bulk ceria (Eg = 3.19 eV). The phytochemicals in the extract reduced the particle size to 3.7 nm � 0.3 nm, as it is evident from the PSA. FT-IR results confirmed the Ce–O stretching bands by showing the peaks at 452 cm􀀀1. The Raman spectrum showed a characteristic peak shift for CONPs at 461.2 cm􀀀1. XRD analysis revealed the cubic fluorite structure of the synthesized nanoparticles with the lattice constant, a of 5.415 Å and unit cell volume, V of 158.813 Å3. XPS signals were used to determine the concentration of Ce3+ and Ce4+ in the prepared CONPs and it was found that major amount of cerium exist in the Ce4+ state. HRTEM images showed spherical shaped particles with an average size of 15 nm. Furthermore, the antibacterial activity of the prepared CONPs was evaluated and their efficacies were compared with the conventional antibiotics using disc diffusion assay against a set of Gram positive (G+) bacteria (Staphylococcus aureus, Streptococcus pneumonia) and Gram negative (G􀀀) bacteria (Pseudomonas aeruginosa, Proteus vulgaris). The results suggested that CONPs showed antibacterial activity with significant variations due to the differences in the membrane structure and cell wall composition among the two groups tested.
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In recent years, there has been a growing interest in researching and developing new antimicrobial agents from various sources to combat the emergence of the microbial resistance. Therefore, a greater attention was paid on antimicrobial activity screening and evaluating methods. Several bioassays are well known and commonly used such as disk-diffusion, well diffusion and broth or agar dilution, but others are not widely used such as flow cytofluorometric and bioluminescent methods because they require specified equipment and further evaluation for reproducibility and standardization, even if they can provide a rapid results of the antimicrobial agent’ effects and a better understood of their impact on the viability and cell damage inflicted to the tested microorganism. In this present review article, an exhaustive list of in vitro antimicrobial susceptibility testing methods and detailed information on their advantages and limitations are reported.
The present research reported the co-precipitation mediated synthesis of mixed metallic oxide composite, CaO/CeO2 using ultrasound-assisted extract of Eichhornia crassipes leaves. Fourier Transform Infrared Spectroscopy (FT-IR), Thermo-gravimetric/Differential Thermal analysis (TG/DTA), X-ray Diffraction (XRD), and Brunauer-Emmet-Tellet (BET) isotherms ensured the formation of the mixed oxide. Further, the CaO/CeO2 composite was tested in the anionic azo dye, Acid Orange 7 (AO7) removal process. The optimal removal of 92.68% was attained in the initial solution pH of 2.0 with the composite dosage of 0.1 g for 10 mg/L of AO7 concentration, operating at the temperature of 301 K. Response Surface Methodology (RSM) and Artificial Neural Network (ANN) techniques were employed to model the dye removal process. A second-order quadratic model from Box-Behnken Design (BBD) predicted and optimized the dye removal percentage with high degree of statistical accuracy (Fcal > Ftab at df=9; p < 0.0001). Likewise, a three-layered ANN model using the Levenberg–Marquardt backpropagation algorithm well predicted the dye adsorption process with the least root mean square error values (RMSE 0.3020). Further, the mean impact value (MIV) method identified pH0 as the most influential batch variable in the AO7 dye adsorption process.
In the present study, green nanoceria (gNC) was synthesized and surface-functionalized (sf-gNC) with amine moieties through chemical means and used as an adsorbent for the removal of Fenalan Yellow G (FYG) from the aqueous solution. Prior to the adsorption process, the optical, structural and textural characteristics of the nanomaterial ensured the presence of highly crystalline and monodisperse nanoceria with the functionalized amine group on their surfaces. The effects of the independent variables of the FYG removal process including initial solution pH, adsorbent dose, initial adsorbate concentration and time were examined for the percent removal. The maximum removal of 93.62% was observed at the pH of 2.0 with the adsorbent dose of 0.1 g for 10 mg/L of FYG dye concentration in 210 min. The equilibrium studies revealed that the maximum adsorption capacity was 25.58 mg/g by monolayer Langmuir model at 303 K and the chemical kinetics results followed pseudo-second-order and chemisorptive Elovich model. The magnitude of the energy variables from the thermodynamic analysis exposed the feasibility and spontaneity of endothermic adsorption. Furthermore, the interactive effects of the screened process variables investigated and optimized through response surface methodology (RSM). Besides, the FYG adsorption behavior was well predicted using artificial neural network (ANN) model with good accuracy (Mean Squared Error < 0.5; Coefficient of determination > 0.99) using 3 input layers, 3 hidden layers and 1 output layer. The study proposed the intrinsic mechanism of adsorbent-adsorbate interactions as either of electrostatic interaction or through surface complexation. Moreover, the prepared amine-modified nanoceria was found to have a minimum of 75% regenerative potential for five adsorption-desorption cycles.
The study investigated the parameter optimization for anthocyanin extraction from egg plant (Solanum melongena) with the approach response surface methodology. Extractions were carried out using acid–ethanol with the temperature range (60–90°C), time (30–90 min) and solid–liquid ratio (1:15–1:30). Three level three factor Box-Behnken design was followed to observe the anthocyanin yield for the studied parameters. The maximum yield of anthocyanin was observed at the temperature 76.5°C in 70 min in the ratio of 1:26.