Ananda Kafle - Academia.edu (original) (raw)

Papers by Ananda Kafle

The size, dispersibility, and fluidity of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), POP... more The size, dispersibility, and fluidity of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), POPC (1-palmitoy-2-oleoyl-sn-glycero-3-phosphocholine), and DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) liposomes doped with β-sitosteryl sulfate (PSO4) were comparatively studied. In all three types of liposomes, PSO4 reduced sizes and enhanced the negative values of the ζ-potential. However, the effect on sizes quantitatively differed in the three cases in a manner dependent on their phase behaviors. PSO4 rigidified each type of membrane in its liquid crystalline phase and fluidized the gel phase. It enhanced the glucose trapping efficiency (TE) of both DPPC and DOPC liposomes. The TE of DPPC first increased with the increasing concentration of PSO4, then decreased gradually. On the other hand, in the case of DOPC, the TE increased significantly upon addition of PSO4, then remained nearly constant. Though the exact dependence of TE on the PSO4 concentration differed in the two cases, ...

Colloid and Polymer Science

New ester functionalized branched anionic surfactant—sodium citronellyl sulfoacetate (SCSA) is de... more New ester functionalized branched anionic surfactant—sodium citronellyl sulfoacetate (SCSA) is developed from naturally occurring acyclic monoterpene citronellol. This new surfactant is investigated for its self-aggregation, detergent, and biodegradation properties. Surface properties of the SCSA are determined by surface tension and conductivity method. Hydrodynamic radius of the micelles formed by the new surfactant is determined by dynamic light scattering technique. Detergency and foaming properties of the new surfactant are determined by Tergotometer and Ross-Miles method respectively. Further, the biodegradation property of the SCSA was determined by the BOD method. The experimental evaluation result establishes SCSA to be a good sustainable alternative to petrochemical derived surfactants. The new surfactant demonstrated good surface activity along with excellent detergent and biodegradation properties.

Langmuir

Phase behavior of systems containing saturated phosphatidylcholine (PC) and plant steroids can be... more Phase behavior of systems containing saturated phosphatidylcholine (PC) and plant steroids can be important for designing new alternative delivery methods. In our previous studies, we found that even a small amount of β-sitosteryl sulfate (PSO4) significantly affects the phase behavior, hydration properties, and liposomal properties of pure saturated phosphatidylcholines (Kafle, et al, Colloids Surf. B 2018, 161, 59-66; Kafle et al 2019, J. Oleo Sci. 2018, 67 (12), 1511-1519). In the current paper, we are reporting the phase behavior of a more complex system consisting of hydrogenated soy lecithin (HLC), which is useful as a carrier in drug delivery systems or in cosmetics, and PSO4. HLC, which is composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA) and lysophosphatidylcholine (LPC), demonstrated a versatile phase behavior. The PC component of HLC was found to separate from the PE and PA components as a result of non-ideal mixing. At room temperature, these two domains represented two distinct gel phases denoted as Lβ1 and Lβ2. The Lβ1 phase selectively underwent transition into the liquid crystalline phase (Lα) at a lower temperature than Lβ2. Upon addition of PSO4, at room temperature, the PC fraction gradually converted into the liquid ordered (Lo) phase while the (PE + PA) fraction remained unaffected. When heated above 60 ℃, the whole material converted into the liquid crystalline phase. The observed fluidizing effect of PSO4 on HLC can find application in preparing vehicles for moisture or drug in cosmetic and pharmaceutical formulations.

Current Opinion in Colloid & Interface Science

Inorganic Chemistry

In page 5609: Their k values, the first-order rate constant, defined by the eq 1 are also listed ... more In page 5609: Their k values, the first-order rate constant, defined by the eq 1 are also listed in Table 1.

Industrial & Engineering Chemistry Research

Ester based anionic surfactant—sodium lauryl sulfoacetate (SLSA)—is one of the most important sur... more Ester based anionic surfactant—sodium lauryl sulfoacetate (SLSA)—is one of the most important surface-active ingredients in several personal care products however no scientific report is available regarding its lyotropic and thermotropic phase behavior in water. In the present study, SLSA and its congener sodium myristyl sulfoacetate (SMSA) are investigated for their self-aggregation properties in aqueous system. Phase transition temperature of these surfactant–water mixtures is determined by differential scanning calorimetry (DSC). Their lyotropic and thermotropic phase behavior in water are investigated by polarized optical microscopy (POM), small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). These surfactants predominantly exist as different types of self-assembled lamellar phases along with or without solid crystalline phases in aqueous system.

Journal of Oleo Science

We investigated the hydration behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers containi... more We investigated the hydration behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers containing sodium β-sitosteryl sulfate (PSO 4). PSO 4 was found to enhance hydration in the headgroup region of DPPC bilayers. Therefore, with the incorporation of PSO 4 into DPPC membranes, the amount of water required to reach the fully hydrated state was enhanced as indicated by the constant values of the main phase transition temperature (T m) and the bilayer repeat distance (d). For example, with the addition of 20 mol% of PSO 4 , the saturation point was shifted to ~70 wt% water compared to ~40 wt% for pure DPPC and 47 wt% for DPPC-cholesterol. The effectiveness of PSO 4 in fluidizing the membrane and enhancing its hydration state can be useful in the pharmaceutical and cosmetic industries.

Colloids and Surfaces B: Biointerfaces

We have studied the phase behavior of dipalmitoylphosphatidylcholine (DPPC) containing sodium β-s... more We have studied the phase behavior of dipalmitoylphosphatidylcholine (DPPC) containing sodium β-sitosteryl sulfate (PSO4). PSO4 was found to lower the phase transition temperature of DPPC to a higher degree than cholesterol or β-sitosterol. It also gave rise to the formation of a modulated (ripple) phase (Pβ) at low to moderate concentrations. At concentrations greater than 25 mol%, it completely changed the membrane into a fluid phase. This shows that PSO4 is capable of disordering the hydrocarbon chains of PC efficiently. The characteristics of PSO4 for fluidizing the membrane can be useful for the pharmaceutical and cosmetics industries.

Journal of Oleo Science

The effect of β-sitosteryl sulfate (PSO 4) on the liposomal size, stability, fluidity, and disper... more The effect of β-sitosteryl sulfate (PSO 4) on the liposomal size, stability, fluidity, and dispersibility of DPPC liposomes prepared by vortex mixing, bath-sonication, and probe-sonication has been studied. PSO 4 significantly decreases the particle size of the multilamellar liposomes (MLVs). The sizes of the vortexmixed and the bath-sonicated liposomes vary as a function of PSO 4 concentration. On the other hand, PSO 4 has only little effect on the particle sizes of probe sonicated liposomes. In some cases, the liposomal stability at higher PSO 4 concentrations depends on the preparation method. PSO 4 improves the dispersibility of the DPPC liposomes and enhances their hydration. It also increases the fluidity of the liposomes prepared by each method. Our results suggest that liposomes consisting of DPPC and PSO 4 can be suitable as a cosmetic or pharmaceutical ingredient for the effective delivery of the active components into the body.

ACS Omega

The micellar solution and the lyotropic liquid crystalline phases formed by gemini surfactants co... more The micellar solution and the lyotropic liquid crystalline phases formed by gemini surfactants containing morpholinium headgroups are investigated for their self-aggregation and physicochemical properties in water. These gemini surfactants demonstrated good surface activity because they are able to undergo micellization at lower concentration and form nanosized micellar aggregates in dilute aqueous solution. The binary mixture of the morpholinium gemini surfactant–water system is investigated over a wide range of concentrations. The micellar solution of the morpholinium gemini surfactants demonstrated Newtonian fluidlike behavior between 10 and 50 wt % as the observed viscosities were independent of the applied shear rate. At higher concentration, morpholinium geminis formed self-assembled lyotropic phases in water. These liquid crystalline phases were characterized by small-angle X-ray scattering and polarized optical microscopy techniques.

Optical transmittance of various natural organic-and synthetic (commercial)-dyes has been measure... more Optical transmittance of various natural organic-and synthetic (commercial)-dyes has been measured in the wavelength range of 310-900 nm. The pure natural dye from raw samples of either flower or root of plants were extracted and dried following standard method. Then the powder of both natural and synthetic dyes were dissolved in ethanol for transmittance measurements by UV-Visible spectrometric technique. In the visible region of electromagnetic radiation, all the natural dye samples show poor absorbance, except Maharanga bicolor. While the synthetic dyes, specifically, Green-VS, Patent-Blue and Black-ADLI show strong absorbance over the wide range in the visible spectrum, demonstrating the prospect of utilizing in the fabrication of dye sensitized solar cells. Uniquely, a natural dye extracted from root of herb Maharanga bicolor shows characteristic peak at around 500 nm, associated with rovibronic transitions.

Natural product communications, 2012

The essential oils from the leaves of Artemisia dubia, A. indica, and A. vulgaris growing wild in... more The essential oils from the leaves of Artemisia dubia, A. indica, and A. vulgaris growing wild in Nepal were obtained by hydrodistillation and analyzed by GC-MS. The major components in A. dubia oil were chrysanthenone (29.0%), coumarin (18.3%), and camphor (16.4%). A. indica oil was dominated by ascaridole (15.4%), isoascaridole (9.9%), trans-p-mentha-2,8-dien-1-ol (9.7%), and trans-verbenol (8.4%). The essential oil of Nepalese A. vulgaris was rich in alpha-thujone (30.5%), 1,8-cineole (12.4%), and camphor (10.3%). The essential oils were screened for phytotoxic activity against Lactuca sativa (lettuce) and Lolium perenne (perennial ryegrass) using both seed germination and seedling growth, and all three Artemisia oils exhibited notable allelopathic activity. A. dubia oil showed in-vitro cytotoxic activity on MCF-7 cells (100% kill at 100 microg/mL) and was also marginally antifungal against Aspergillus niger (MIC = 313 microg/mL). DFT calculations (B3LYP/6-31G*) revealed thermal ...

Journal of Oleo Science

Introduction Phosphatidylcholines PC are amphiphilic molecules having a pair of acyl chains linke... more Introduction Phosphatidylcholines PC are amphiphilic molecules having a pair of acyl chains linked to the phosphocholine head group. Their structure imparts them with amphiphilicity and hence, in the presence of water, they form lamellar bilayers. PC bilayers are the building blocks of biological membranes. Depending on the temperature and the presence of other biomolecules, they can assume different structural forms known as phases. The phase behaviors of PCs are of prime importance in regulating the functions of biological membranes 1 6. Saturated phospholipids e.g., 1,2-dimyristoyl-sn-glycero-3-phosphocholine DMPC , DPPC, and DSPC are widely used as model systems for understanding the behavior of biological membranes 7 9. When hydrated, they exhibit three main phases, namely, the gel phase L β , the ripple phase P β , and the liquid crystalline L α phase. The gel phase L β exists below a characteristic temperature known as the phase transition temperature. It is characterized by the presence of all-trans acyl chains packed together to

Sci

In response to increasing natural surfactant demand and environmental concerns, natural plant-bas... more In response to increasing natural surfactant demand and environmental concerns, natural plant-based surfactants have been replacing synthetic ones. Saponins belong to a class of plant metabolites with surfactant properties that are widely distributed in nature. They are eco-friendly because of their natural origin and biodegradable. To date, many plant-based saponins have been investigated for their surface activity. An overview of saponins with a particular focus on their surface-active properties is presented in this article. For this purpose, works published in the past few decades, which report better surfactant relevant properties of saponins than synthetic ones, were extensively studied. The investigations on the potential surfactant application of saponins are also documented. Moreover, some biological activities of saponins such as antimicrobial activity, antidiabetic activity, adjuvant potentials, anticancer activity, and others are reported. Plants rich in saponins are wid...

The size, dispersibility, and fluidity of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), POP... more The size, dispersibility, and fluidity of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), POPC (1-palmitoy-2-oleoyl-sn-glycero-3-phosphocholine), and DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) liposomes doped with β-sitosteryl sulfate (PSO4) were comparatively studied. In all three types of liposomes, PSO4 reduced sizes and enhanced the negative values of the ζ-potential. However, the effect on sizes quantitatively differed in the three cases in a manner dependent on their phase behaviors. PSO4 rigidified each type of membrane in its liquid crystalline phase and fluidized the gel phase. It enhanced the glucose trapping efficiency (TE) of both DPPC and DOPC liposomes. The TE of DPPC first increased with the increasing concentration of PSO4, then decreased gradually. On the other hand, in the case of DOPC, the TE increased significantly upon addition of PSO4, then remained nearly constant. Though the exact dependence of TE on the PSO4 concentration differed in the two cases, ...

Colloid and Polymer Science

New ester functionalized branched anionic surfactant—sodium citronellyl sulfoacetate (SCSA) is de... more New ester functionalized branched anionic surfactant—sodium citronellyl sulfoacetate (SCSA) is developed from naturally occurring acyclic monoterpene citronellol. This new surfactant is investigated for its self-aggregation, detergent, and biodegradation properties. Surface properties of the SCSA are determined by surface tension and conductivity method. Hydrodynamic radius of the micelles formed by the new surfactant is determined by dynamic light scattering technique. Detergency and foaming properties of the new surfactant are determined by Tergotometer and Ross-Miles method respectively. Further, the biodegradation property of the SCSA was determined by the BOD method. The experimental evaluation result establishes SCSA to be a good sustainable alternative to petrochemical derived surfactants. The new surfactant demonstrated good surface activity along with excellent detergent and biodegradation properties.

Langmuir

Phase behavior of systems containing saturated phosphatidylcholine (PC) and plant steroids can be... more Phase behavior of systems containing saturated phosphatidylcholine (PC) and plant steroids can be important for designing new alternative delivery methods. In our previous studies, we found that even a small amount of β-sitosteryl sulfate (PSO4) significantly affects the phase behavior, hydration properties, and liposomal properties of pure saturated phosphatidylcholines (Kafle, et al, Colloids Surf. B 2018, 161, 59-66; Kafle et al 2019, J. Oleo Sci. 2018, 67 (12), 1511-1519). In the current paper, we are reporting the phase behavior of a more complex system consisting of hydrogenated soy lecithin (HLC), which is useful as a carrier in drug delivery systems or in cosmetics, and PSO4. HLC, which is composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidic acid (PA) and lysophosphatidylcholine (LPC), demonstrated a versatile phase behavior. The PC component of HLC was found to separate from the PE and PA components as a result of non-ideal mixing. At room temperature, these two domains represented two distinct gel phases denoted as Lβ1 and Lβ2. The Lβ1 phase selectively underwent transition into the liquid crystalline phase (Lα) at a lower temperature than Lβ2. Upon addition of PSO4, at room temperature, the PC fraction gradually converted into the liquid ordered (Lo) phase while the (PE + PA) fraction remained unaffected. When heated above 60 ℃, the whole material converted into the liquid crystalline phase. The observed fluidizing effect of PSO4 on HLC can find application in preparing vehicles for moisture or drug in cosmetic and pharmaceutical formulations.

Current Opinion in Colloid & Interface Science

Inorganic Chemistry

In page 5609: Their k values, the first-order rate constant, defined by the eq 1 are also listed ... more In page 5609: Their k values, the first-order rate constant, defined by the eq 1 are also listed in Table 1.

Industrial & Engineering Chemistry Research

Ester based anionic surfactant—sodium lauryl sulfoacetate (SLSA)—is one of the most important sur... more Ester based anionic surfactant—sodium lauryl sulfoacetate (SLSA)—is one of the most important surface-active ingredients in several personal care products however no scientific report is available regarding its lyotropic and thermotropic phase behavior in water. In the present study, SLSA and its congener sodium myristyl sulfoacetate (SMSA) are investigated for their self-aggregation properties in aqueous system. Phase transition temperature of these surfactant–water mixtures is determined by differential scanning calorimetry (DSC). Their lyotropic and thermotropic phase behavior in water are investigated by polarized optical microscopy (POM), small-angle X-ray scattering (SAXS) and wide-angle X-ray scattering (WAXS). These surfactants predominantly exist as different types of self-assembled lamellar phases along with or without solid crystalline phases in aqueous system.

Journal of Oleo Science

We investigated the hydration behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers containi... more We investigated the hydration behavior of dipalmitoylphosphatidylcholine (DPPC) bilayers containing sodium β-sitosteryl sulfate (PSO 4). PSO 4 was found to enhance hydration in the headgroup region of DPPC bilayers. Therefore, with the incorporation of PSO 4 into DPPC membranes, the amount of water required to reach the fully hydrated state was enhanced as indicated by the constant values of the main phase transition temperature (T m) and the bilayer repeat distance (d). For example, with the addition of 20 mol% of PSO 4 , the saturation point was shifted to ~70 wt% water compared to ~40 wt% for pure DPPC and 47 wt% for DPPC-cholesterol. The effectiveness of PSO 4 in fluidizing the membrane and enhancing its hydration state can be useful in the pharmaceutical and cosmetic industries.

Colloids and Surfaces B: Biointerfaces

We have studied the phase behavior of dipalmitoylphosphatidylcholine (DPPC) containing sodium β-s... more We have studied the phase behavior of dipalmitoylphosphatidylcholine (DPPC) containing sodium β-sitosteryl sulfate (PSO4). PSO4 was found to lower the phase transition temperature of DPPC to a higher degree than cholesterol or β-sitosterol. It also gave rise to the formation of a modulated (ripple) phase (Pβ) at low to moderate concentrations. At concentrations greater than 25 mol%, it completely changed the membrane into a fluid phase. This shows that PSO4 is capable of disordering the hydrocarbon chains of PC efficiently. The characteristics of PSO4 for fluidizing the membrane can be useful for the pharmaceutical and cosmetics industries.

Journal of Oleo Science

The effect of β-sitosteryl sulfate (PSO 4) on the liposomal size, stability, fluidity, and disper... more The effect of β-sitosteryl sulfate (PSO 4) on the liposomal size, stability, fluidity, and dispersibility of DPPC liposomes prepared by vortex mixing, bath-sonication, and probe-sonication has been studied. PSO 4 significantly decreases the particle size of the multilamellar liposomes (MLVs). The sizes of the vortexmixed and the bath-sonicated liposomes vary as a function of PSO 4 concentration. On the other hand, PSO 4 has only little effect on the particle sizes of probe sonicated liposomes. In some cases, the liposomal stability at higher PSO 4 concentrations depends on the preparation method. PSO 4 improves the dispersibility of the DPPC liposomes and enhances their hydration. It also increases the fluidity of the liposomes prepared by each method. Our results suggest that liposomes consisting of DPPC and PSO 4 can be suitable as a cosmetic or pharmaceutical ingredient for the effective delivery of the active components into the body.

ACS Omega

The micellar solution and the lyotropic liquid crystalline phases formed by gemini surfactants co... more The micellar solution and the lyotropic liquid crystalline phases formed by gemini surfactants containing morpholinium headgroups are investigated for their self-aggregation and physicochemical properties in water. These gemini surfactants demonstrated good surface activity because they are able to undergo micellization at lower concentration and form nanosized micellar aggregates in dilute aqueous solution. The binary mixture of the morpholinium gemini surfactant–water system is investigated over a wide range of concentrations. The micellar solution of the morpholinium gemini surfactants demonstrated Newtonian fluidlike behavior between 10 and 50 wt % as the observed viscosities were independent of the applied shear rate. At higher concentration, morpholinium geminis formed self-assembled lyotropic phases in water. These liquid crystalline phases were characterized by small-angle X-ray scattering and polarized optical microscopy techniques.

Optical transmittance of various natural organic-and synthetic (commercial)-dyes has been measure... more Optical transmittance of various natural organic-and synthetic (commercial)-dyes has been measured in the wavelength range of 310-900 nm. The pure natural dye from raw samples of either flower or root of plants were extracted and dried following standard method. Then the powder of both natural and synthetic dyes were dissolved in ethanol for transmittance measurements by UV-Visible spectrometric technique. In the visible region of electromagnetic radiation, all the natural dye samples show poor absorbance, except Maharanga bicolor. While the synthetic dyes, specifically, Green-VS, Patent-Blue and Black-ADLI show strong absorbance over the wide range in the visible spectrum, demonstrating the prospect of utilizing in the fabrication of dye sensitized solar cells. Uniquely, a natural dye extracted from root of herb Maharanga bicolor shows characteristic peak at around 500 nm, associated with rovibronic transitions.

Natural product communications, 2012

The essential oils from the leaves of Artemisia dubia, A. indica, and A. vulgaris growing wild in... more The essential oils from the leaves of Artemisia dubia, A. indica, and A. vulgaris growing wild in Nepal were obtained by hydrodistillation and analyzed by GC-MS. The major components in A. dubia oil were chrysanthenone (29.0%), coumarin (18.3%), and camphor (16.4%). A. indica oil was dominated by ascaridole (15.4%), isoascaridole (9.9%), trans-p-mentha-2,8-dien-1-ol (9.7%), and trans-verbenol (8.4%). The essential oil of Nepalese A. vulgaris was rich in alpha-thujone (30.5%), 1,8-cineole (12.4%), and camphor (10.3%). The essential oils were screened for phytotoxic activity against Lactuca sativa (lettuce) and Lolium perenne (perennial ryegrass) using both seed germination and seedling growth, and all three Artemisia oils exhibited notable allelopathic activity. A. dubia oil showed in-vitro cytotoxic activity on MCF-7 cells (100% kill at 100 microg/mL) and was also marginally antifungal against Aspergillus niger (MIC = 313 microg/mL). DFT calculations (B3LYP/6-31G*) revealed thermal ...

Journal of Oleo Science

Introduction Phosphatidylcholines PC are amphiphilic molecules having a pair of acyl chains linke... more Introduction Phosphatidylcholines PC are amphiphilic molecules having a pair of acyl chains linked to the phosphocholine head group. Their structure imparts them with amphiphilicity and hence, in the presence of water, they form lamellar bilayers. PC bilayers are the building blocks of biological membranes. Depending on the temperature and the presence of other biomolecules, they can assume different structural forms known as phases. The phase behaviors of PCs are of prime importance in regulating the functions of biological membranes 1 6. Saturated phospholipids e.g., 1,2-dimyristoyl-sn-glycero-3-phosphocholine DMPC , DPPC, and DSPC are widely used as model systems for understanding the behavior of biological membranes 7 9. When hydrated, they exhibit three main phases, namely, the gel phase L β , the ripple phase P β , and the liquid crystalline L α phase. The gel phase L β exists below a characteristic temperature known as the phase transition temperature. It is characterized by the presence of all-trans acyl chains packed together to

Sci

In response to increasing natural surfactant demand and environmental concerns, natural plant-bas... more In response to increasing natural surfactant demand and environmental concerns, natural plant-based surfactants have been replacing synthetic ones. Saponins belong to a class of plant metabolites with surfactant properties that are widely distributed in nature. They are eco-friendly because of their natural origin and biodegradable. To date, many plant-based saponins have been investigated for their surface activity. An overview of saponins with a particular focus on their surface-active properties is presented in this article. For this purpose, works published in the past few decades, which report better surfactant relevant properties of saponins than synthetic ones, were extensively studied. The investigations on the potential surfactant application of saponins are also documented. Moreover, some biological activities of saponins such as antimicrobial activity, antidiabetic activity, adjuvant potentials, anticancer activity, and others are reported. Plants rich in saponins are wid...