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The purpose of this paper is to extract, characterise and quantify curcumin from selected Zingiberaceae of “kunyit” or turmeric (Curcuma longa), “temu lawak” or Javanese turmeric (Curcuma xanthorrhiza), “temu pauh” (Curcuma mangga), “lempoyang” (Zingiber zerumbet) and “bonglai” (Zingiber cassumunar) using alkaline and chemical-based extraction method for antimicrobial and antioxidant activities.

Through the alkaline-based extraction method, all parts of rhizome samples were freeze-dried for 72 h before grounded into a fine powder and kept at −20°C. The powdered sample (0.1 g) was weighed and placed in a 50 mL tube. About 20 mL of 2 M NaOH solution was added into the tube. The solution was allowed to stand for 30 min. Then, 20 mL of ethyl acetate was added into the tube. The solution was mixed well then centrifuged at 13,500 rpm for 3 min. The upper layer was collected using a pipette. The process was repeated until the upper layer became almost colourless. The collected ethyl acetate solution was concentrated using a rotary evaporator to remove the ethyl acetate from the extracted compound. The concentrated curcumin was placed in a universal bottle, which was then dried from the remaining ethyl acetate using nitrogen drying process. The dried curcumin was then stored inside the freezer at −20ºC. The antimicrobial activities were using agar diffusion method against bacterial and fungi, while the antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assay.

All the samples successfully showed a single peak (curcumin) that gained from the high-performance liquid chromatography (HPLC) chromatogram analysis (at 425 nm) using the alkaline-based extraction method and the highest curcumin content was in turmeric (12.95 ± 1.07mg/g DW). At 10.0 mg/mL curcumin concentration, the best antibacterial activity was against on methicillin-resistant staphylococcus aureus (MRSA) with 7.50 ± 0.71 mm inhibition zone, while the best antifungal activity was against on Aspergillus niger with 8.00 ± 0.41 mm inhibition zone. The DPPH antioxidant test resulted in the highest inhibition (110.41 per cent) was at 0.25 mg/mL curcumin concentration.

Through HPLC analysis, all samples successfully showed a single peak of curcumin at 425 nm. The total carotenoid determination from turmeric revealed that the samples content was substantially higher using alkaline-based extraction (18.40 ± 0.07 mg/g DW) compared to chemical-based extraction (9.42 ± 0.20 mg/g ± SD).

The purpose of this study is to evaluate the pattern of carotenoids distribution in three underutilized Malaysian ‘ulam’ or traditional vegetables in Malaysia (Averrhoa carambola, Manihot esculenta and Ipomoea batatas) and their valuable pro-vitamin A activities. These assessments will yield valuable knowledge and insight into the importance of these underutilized traditional vegetables and highlight their potential for applications in medicinal and functional colorant industries.

In this study, the authors have evaluated the distribution of carotenoid compounds in aerial organs of three underutilized traditional vegetables (Averrhoa carambola, Manihot esculenta and Ipomoea batatas). The content of the individual carotenoids were quantified using high-performance liquid chromatography (HPLC) and the organ with the highest accumulation of these compounds were identified. Their valuable pro-vitamin A activities were also reported to indicate their medicinal potential which can further be exploited as pharmacologically active natural colorants and in other applications.

In total, three major chromatographic peaks corresponding to lutein, violaxanthin and β-carotene were observed through HPLC. Among the compounds detected, lutein and β-carotene were the most abundant carotenoids found in both shoots and petioles of all three species. Violaxanthin was only detected in I. batatas shoots. Overall, carotenoid content was observed to be higher in the shoots than in the petioles, where I. batatas contained the highest amount of total carotenoid, followed by M. esculenta and A. carambola. The opposite trend was observed in the petioles, where A. carambola petioles had the highest carotenoid content, while I. batatas contained the least.

The distribution and abundance of these individual carotenoids suggested that the petioles contained the highest amount of carotenoid, contributing to its high pro-vitamin A activity, and could be potentially useful for medicinal application, as it can act as storage site that is not as prone to natural drying or degradation during harvest and sample storage. Future research work should include improvements in the extraction and purification procedures as well as robust identification methods which may lead to better detection and identification of other compounds that could attribute to its bioactivity, to complement the findings of the current study.

This analysis provides valuable information on the importance of underutilized traditional vegetables as important biofactories for sustainable production of valuable pigments (such as carotenoids) with medicinal benefits and can further be exploited in various industries, such as in formulation of functional natural colorants. This study also highlights the importance of petiole as a storage site of pharmacologically active compounds that is not as prone to natural drying or degradation during harvest and sample storage.

To date, there is no previous report found on comparative analysis of carotenoid content and quantification of individual carotenoid concentration in the edible aerial parts of Averrhoa carambola, Manihot esculenta and Ipomoea batatas, although they have been traditionally consumed as “ulam” in Malaysia. Therefore, the results reported in this study provide new insights on carotenoid accumulation in the selected ‘ulam’ species.

This paper aims to study the effect of different organic solvents on the extraction of pigments present in callus cultures of E. cinerascens.

Attempts have been made to extract pigments from callus cultures through tissue culture system as an alternative replacement for conventional plant cultivation as tissue culture provides unlimited supplies of plant samples. Callus of E. cinerascens was induced from stem explant cultured in Murashige and Skoog medium supplemented with combination of 0.5 mg/L 6-benzylaminopurine and 0.5 mg/L α-naphthaleneacetic acid maintained under photoperiod of 16 h light and 8 h dark. Fresh samples of the callus were harvested and dissolved in various types and concentrations of solvents such as 100 per cent acetone, 80 per cent acetone, 95 per cent ethanol, 100 per cent methanol and 90 per cent methanol. Each of the mixtures was directly centrifuged to get clear supernatant containing pigments of interest. The pigments were detected and subsequently quantified via two simple techniques, ultraviolet-visible (UV-Vis) spectrophotometer and thin layer chromatography (TLC).

UV-Vis spectrophotometer detected two families of pigments present in the callus cultures, namely, carotenoids (carotene and xanthophyll) and tetrapyrroles (chlorophyll a and b). Pigment contents in various solvent extractions were estimated using spectroscopic quantification equations established. Through TLC, spots were seen on the plates, and Rf values of each spots were assessed to indicate the possible existence of carotenoids and tetrapyrroles.

This preliminary study offers significant finding for further advance research related on natural pigments extracted from E. cinerascens that would provide profits in the future applications, especially in food industry, medicine, agriculture, etc.

The purpose of the study is to identify the high valuable compounds which are crocin, crocetin and zeaxanthin in the stigmas and stamens of Crocus sativus grown under controlled environment in Malaysia.

Spectrophotometry and high-performance liquid chromatography (HPLC) analysis were used to identify and measure crocin, crocetin and zeaxanthin content qualitatively and quantitatively in the stigmas and stamens of C. sativus grown under controlled environment in Malaysia.

The results of this study showed that crocin, crocetin and zeaxanthin were detected in the stigmas. However, among those three compounds, only crocetin was detected in the stamens. In the stigmas, the detectable level of crocin was high compared to crocetin and zeaxanthin. It was also found that crocetin was higher in the stamens compared to in the stigmas.

This is the first attempt in Malaysia that the stigmas and stamens were directly purified from the natural sources by means of no addition of preservatives as C. sativus has never been grown here before. Furthermore, limited reports are available regarding the identification of compounds in saffron stamens.

The purpose of this paper is to validate the antimicrobial activity (both antibacterial and antifungal) of in vivo and in vitro ethanolic anthocyanin extracts of Clitoria ternatea L. (vivid blue flower butterfly-pea) and Dioscorea alata L. (purple yam) against selected bacteria (Bacillus subtilis, Staphylococcus aureus and Escherichia coli) and fungi (Fusarium sp., Aspergillus niger and Trichoderma sp.).

The freeze-dried samples (0.2 g) from in vivo vivid blue flowers of C. ternatea L. were extracted using 10 mL ethanol (produced ethanolic red extraction) and 10 mL distilled water (produced aqueous blue extraction) separately. Two-month-old in vitro callus samples (0.2 g) were only extracted using 10 mL ethanol. The anthocyanin extractions were separated with the addition (several times) of ethyl acetate and distilled water (1:2:3) to remove stilbenoids, chlorophyll, less polar flavonoids and other non-polar compounds. Furthermore, the antimicrobial properties were determined using agar diffusion technique. Three bacteria (B. subtilis, S. aureus and E. coli) and fungi (F. sp., A. niger and T. sp.) were streaked on bacteria agar and dextrose agar, respectively, using “hockey stick”. Then, the sterile paper discs (6 mm diameter) were pipetted with 20 µL of 1,010 CFU/mL chloramphenicol (as control for antibacterial) and carbendazim (as control for antifungal) in vivo and in vitro extracts. The plates were incubated at room temperature for 48 h, and the inhibition zones were measured.

Based on the results, both in vivo and in vitro ethanolic extracts from vivid blue flowers of C. ternatea L. showed the best antibacterial activity against the same bacteria (B. subtilis), 11 and 10 mm inhibition zones, respectively. However, different antifungal activity was detected in in vitro ethanolic callus extract (12 mm), which was against T. sp., contrary to in vivo ethanolic extract (10 mm), which was against F. sp.; antibacterial activity of D. alata L. was seen against the same bacteria (E. coli) with the highest inhibition zone for in vivo extract (8.8 mm), followed by in vitro extract (7.8 mm).

Anthocyanins are responsible for the water soluble and vacuolar, pink, red, purple and blue pigments present in coloured plant pigments. These pigments (pink, red, purple and blue) are of important agronomic value in many crops and ornamental plants. However, anthocyanins are not stable and are easy to degrade and fade whenever exposed to light.

Plant extracts containing bioactive agents with antimicrobial properties have been found to be useful in treating bacterial and fungal infections, as well as showed multiple antibiotic resistance.

Both in vivo and in vitro extracts from vivid blue flower petals (C. ternatea L.) and purple yam (D. alata L.) have important applications as natural antimicrobial (antibacterial and antifungal) agents in the coating industry, instead of natural pharmaceutical products.

The purpose of this study is to evaluate the content of bioactive pigments in coloured callus of Azadirachta indica and to understand the correlation between the callus colours with their bioactive constituents, antioxidant properties and cytotoxicity. These assessments will yield valuable insight into the use of in vitro-derived pigments for possible use as functional natural colourants.

In this study, the authors have successfully developed a protocol to produce leaf-derived callus of various colours with enhanced content of bioactive pigments in A. indica through plant tissue culture. Comparative analysis of the pigments content (chlorophyll, carotenoid, phenolics and anthocyanins) in the coloured callus was conducted, followed by evaluation of its bioactive properties. The antioxidant properties against 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, ferric reducing antioxidant power and cytotox activities of the coloured callus extracts were also reported.

Callus of various colours were successfully produced in A. indica through plant tissue culture, and their valuable pigment content and bioactivity were evaluated. The green callus contained the highest amount of anthocyanin, followed by brown and cream callus. The total anthocyanin contents in both the green and brown callus was more than two-fold higher than that in cream callus. Contrasting observation was obtained for total phenolic content (TPC), where the TPC of cream callus was significantly higher than that in brown callus. Nevertheless, the green callus also exhibited the highest TPC. Green callus also contained the highest amount of total chlorophyll and carotenoid, as well as exhibited the highest antioxidant potential, and was found to be the only extract with active cytotox activity against SKOV-3 cells. Correlation analysis revealed that the excellent bioactivity exhibited by the coloured extracts was strongly correlated with the bioactive pigments present in the callus.

The major bioactive compounds identified in the methanolic extracts of A. indica coloured callus are anthocyanins, phenolics, chlorophylls and carotenoids. Future research work should include improvements in the extraction and identification methods, which may lead to detection and determination of other compounds that could attribute to its bioactivity, to complement the findings of the current study.

This analysis provides valuable information on the application of plant tissue culture as an alternative source for sustainable production of major pigments with medicinal benefits in A. indica for possible use as functional natural colourants.

A comparative study on bioactive pigment production in coloured callus from A. indica leaves and its antioxidant potential and cytotoxicity is original. To the best of the authors’ knowledge, this is the first report detailing a comparative evaluation on the production of coloured callus in A. indica and its relative biochemical composition and bioactive properties.

The purpose of the present study is to understand the role of auxin and cytokinin in stimulating the production of pigmented callus in Orthosiphon stamineus and to gain correlation between the callus colours with their antioxidant capacity and bioactive constituents.

In this study, plant tissue culture was used to induce production of callus of various colours from leaf explants of O. stamineus, via manipulation of plant hormones (0-2.0 mg L⁻¹ indole-3-acetic acid [IAA] and Kinetin [Kin]). The coloured callus was subjected to solvent extraction and used for quantification of its carotenoid, chlorophyll, anthocyanin and phenolic contents. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity of the extracts was also evaluated, before and after four weeks of storage at −20°C.

The highest mean (per cent) explants that produced roots (93.33 ± 0.05 per cent) were observed when the cultures were supplemented with 2.0 mg L⁻¹ IAA. The colour of the callus changed with time, from green to cream to brown after two and four months of culture, respectively. Optimum production of green callus was achieved with addition of 2.0 mg L⁻¹ Kin plus 1.0-2.0 mg L⁻¹ IAA to the media, while cream callus in 0.5 mg L⁻¹ Kin plus 2.0 mg L⁻¹ IAA and brown callus in 0.5 mg L⁻¹ Kin plus 1.5 mg L⁻¹ IAA. Green callus was found to contain the highest amount of chlorophylls, carotenoid and anthocyanin, while cream callus contained the highest amount of phenolic compounds. The amount of pigments and secondary metabolites in the callus extracts decreased after four weeks of storage, except anthocyanin. The antioxidant potential of the extracts also increased after storage.

The major compounds identified in the methanolic extracts of O. stamineus-coloured callus are chlorophylls, carotenoids, flavonoids and phenolic acids. Future research work should include improvements in the extraction and identification methods which may lead to detection of other compounds that could attribute to the antioxidant capacity, to complement the findings of the current study.

This analysis provides valuable information on the application of IAA and Kinetin (Kin) to manipulate the content of major pigments with medicinal benefits in O. stamineus by using the plant tissue culture system.

A comparative study on antioxidant capacity and bioactive constituents of pigmented callus from O. stamineus leaves is original. To the best of the authors’ knowledge, this is the first attempt of comparative evaluation on antioxidant potential of O. stamineus-coloured callus produced using IAA and Kin.

This study aims to ascertain consumption values of Muslim tourists, attitudes, satisfaction and loyalty towards a Muslim-friendly accommodation, which has gained recognition from the Malaysian Government. Subsequently, an overall Muslim-friendly image was examined as a moderating variable within the associated relationship.

A quantitative research design with a purposive sampling technique was chosen through a sample size of 378 people in Malaysia and distributed via social media. The respondents were selected based on the Muslim-friendly accommodation recognition (MFAR) initiatives, a procedure of accreditation which acknowledges Muslim-friendly accommodation for tourists. To obtain data from those travellers, structured questionnaires were used. SmartPLS was used for data analysis in this study.

The values which were found to have an influence on attitude towards a Muslim-friendly accommodation are related to social, emotional, economic, functional, monetary and epistemic elements. On the other hand, hedonic, conditional, Islamic and altruistic values were found to be insignificant in determining the attitude towards a Muslim-friendly accommodation. Subsequently, an overall Muslim-friendly image was found to moderate the relationship between social, monetary and altruistic values and its link concerning attitude towards the accommodation, while the rest of the relationships were not significant. More importantly, attitude seems to have an impact on satisfaction, as well as its loyalty towards a Muslim-friendly accommodation.

Firstly, it begins with understanding Malaysia, one of the developing countries in Southeast Asia. Secondly, data was collected from participants using a survey method, from purposive sampling which may limit the findings’ generalizability. Thirdly, this study focussed exclusively on the perceived value dimensions associated with Muslim-friendly accommodation, thus, disregarding consumers who may associate with other types of tourism and hospitality elements.

The results provide a fresh insight and a better understanding regarding the consumption values and all of its related components towards customer loyalty of the Muslim-friendly accommodation in Malaysia. In addition, the findings deliver new information and a deeper understanding of relevant values in Malaysia’s Muslim-friendly accommodation, which can be used as a standard guideline by industry practitioners, local and abroad.

This research supports service providers in developing effective brand management strategies for their own businesses. Apparently, this study discovers that emotional values tend to be the most important values in determining attitude towards Muslim-friendly accommodation.

To the best of the authors’ knowledge, this is one of the studies examining the overall perceived Muslim-friendly image within the consumption values that are relevant from an Islamic viewpoint. It provides policymakers, as well as the industry players, some reliable approaches for enhancing Muslim-friendly accommodation.

The purpose of this paper is to present the investigation of the pressure-driven flow of aluminum oxide-water based nanofluid with the combined effect of entropy generation and radiative electro-magnetohydrodynamics filled with porous media inside a symmetric wavy channel.

The non-linear coupled differential equations are first converted into a number of ordinary differential equations with appropriate transformations and then analytical solutions are obtained by homotopic approach. Numerical simulation has been designed by the most efficient approach known homotopic-based Mathematica package BVPh 2.0 technique. The long wavelength approximation over the channel walls is taken into account. The obtained analytical results have been validated through graphs to infer the role of most involved pertinent parameters, whereas the characteristics of heat transfer and shear stress phenomena are presented and examined numerically.

It is found that the velocity profile decreases near to the channel. This is in accordance with the physical expectation because resistive force acts opposite the direction of fluid motion, which causes a decrease in velocity. It is seen that when the electromagnetic parameter increases then the velocity close to the central walls decreases whereas quite an opposite behavior is noted near to the walls. This happens because of the combined influence of electro-magnetohydrodynamics. It is perceived that by increasing the magnetic field parameter, Darcy number, radiation parameter, electromagnetic parameter and the temperature profile increases, and this is because of thermal buoyancy effect. For radiation and electromagnetic parameters, energy loss at the lower wall has substantial impact compared to the upper wall. Residual error minimizes at 20th order iterations.

The proposed prospective model is designed to explore the simultaneous effects of aluminum oxide-water base nanofluid, electro-magnetohydrodynamics and entropy generation through porous media. To the best of author’s knowledge, this model is reported for the first time.

The growing competition between the developing halal market and the countries in halal market has enhanced the interest of researchers in this field in recent years. In this context, this study aims to examine the studies published in the international literature on halal tourism between 1975 and 2019 in terms of bibliometric characteristics and to reveal tendencies and trends of these publications within the framework of certain parameters.

In accordance with this purpose, the topic of “halal tourism” was searched in the database of “Web of Science Core Collection,” and bibliometrics data in regard to the publications were reached. Publications on halal tourism were examined in the context of years, numbers, genres, research fields, fields of study, journals in which they are found, the number of authors and page number of publications, research approaches of publications, themes of publications, country where the research data was collected (examined), names of the authors in the publications and publication numbers of the authors, and the number of citations.

In this paper, it was determined that the studies in the field of halal tourism increased in recent years. It was concluded that these studies were mainly carried out after 2011 and showed a large increase in 2016, the majority of the publications were in the form of study-paper and the average number of citations in the field was 3.1, and h-index number was seven.

This paper is based on bibliometric analysis. Bibliometric analyses were performed on the “Web of Science Core Collection.” Because of database searches were made only on “Web of Science Core Collection,” the publications that were not scanned here could not be analyzed.

This paper examined the studies on halal tourism between 1975 and 2019 with a bibliometric analysis technique. Thus, it is aimed to learn more about halal tourism and to provide the researchers who work in this field with information about the structure of this field.