Indigenous knowledge of dye-yielding plants among Bai communities in Dali, Northwest Yunnan, China

A review of history, properties, classification, applications and challenges of natural and synthetic dyes

Natural dyes have been used for centuries for coloring textiles, food, and other materials. Synthetic dyes are particularly popular due to their ease of use, wide range of available colors, and fastness. However, their usage comes with significant environmental and health challenges. In recent years, there has been a renewed interest in natural dyes due to their eco-friendliness, ready availability, affordability, non-toxicity, and sustainability. Hence, natural dyes are fast gaining popularity as better alternatives to synthetic dyes. Nature is blessed with a rich diversity of plant species with varying colors and properties which can be harnessed in textile, printing, cosmetics, and food industries. This paper presents a comprehensive review on natural and synthetic dyes with particular focus on their history, properties, classification, extraction methods, applications, and health challenges. Although many plants have been suggested as potential sources of natural dyes, there is insufficient information on their exploration and application. Additionally, chemical analyses of these dyes have not been extensively done. Overall, the results of studies conducted so far identified a number of promising taxa for further investigation as plant-based dyes with many indigenous plants as potential sources of natural dyes.

"Purplish Blue" or "Greenish Grey"? Indigo Qualities and Extraction Yields from Six Species

Indigo quality is determined by its indigotin content. Another quality indicator is colour. For an evaluation of species, indigo samples from Indigofera tinctoria, Indigofera suffruticosa, Indigofera arrecta, Persicaria tinctoria, Strobilanthes cusia and Wrightia laevis cultivated in Austria and China were visually classified and analysed spectrophotometrically and using a L*a*b* measuring device. In addition to a standardised hot-extraction method without lime, some samples were extracted simulating traditional methods at ambient temperatures using lime. The highest indigotin contents were achieved with Indigofera arrecta (55%, Austria) and Strobilanthes cusia (56%, China). There were no statistically significant differences between the indigo extraction yields of the species cultivated in Austria, but Indigofera arrecta and Persicaria tinctoria had statistically significantly higher indigotin extraction yields than Indigofera tinctoria and Indigofera suffruticosa. From the species extracted in China, Strobilanthes cusia showed higher values in all parameters than Indigofera tinctoria, Indigofera suffruticosa and Wrightia laevis. Compared with the standardised method, the method simulating local practice yielded more indigo but had a lower indigotin content; the indigotin extraction yields did not differ greatly. L*a*b* values enabled precise estimations of the indigotin content, making it an interesting option for quality control, as inexpensive, easy-to-handle L*a*b* measuring instruments have become available.

Meizi-Consuming Culture That Fostered the Sustainable Use of Plum Resources in Dali of China: An Ethnobotanical Study

Prunus mume has been cultivated for more than three millennia with important edible, ornamental, and medicinal value. Due to its sour taste, the Prunus mume fruit (called Meizi in Chinese and Ume in Japanese) is not very popular compared to other fruits. It is, however, a very favorite food for the Bai people living in Eryuan County, Dali of Yunnan, China. The local people are masters of making various local products with plum in different ways. In this research, we conducted field investigations in Eryuan County using ethnobotanical methods from August 2019 to July 2021, focusing on the Prunus mume (for its edible fruits). A total of 76 key informants participated in our semi-structured interviews. The survey recorded 37 species (and varieties) belonging to 11 families related to the Bai people’s Meizi-consuming culture. Among them, there are 14 taxa of plum resources, including one original species and 13 varieties. These 37 species are either used as substitutes for plum due to their similar taste or as seasonings to improve the sour taste of plum. The higher Cultural Food Significance Index value implies that Prunus mume, Chaenomeles speciosa, Phyllanthus emblica, Prunus salicina, and Chaenomeles cathayensis have high acceptance and use value in the Bai communities. Among the various local products traditionally made by the Bai people, carved plums, preserved plums, perilla-wrapped plums, and stewed plums are the most famous and popular categories in the traditional markets. Currently, the plum business based on the traditional Meizi-consuming culture of the Bai people is already one of Eryuan’s economic pillars. This study showed that plums play an important role in expressing the local cultural diversity, and they also help the local people by improving their livelihood through their edible value. In turn, for the sustainable use of plum resources, the Bai people positively manage local forests through a series of measures to protect the diversity of plum resources and related plant communities.

Plants for making wooden bowls and related traditional knowledge in the Gyirong Valley, Tibet, China

BACKGROUND

The wooden bowl is an important symbol of the Tibetan cultures, yet, in China, little has been documented regarding the raw materials used to make these items as well as their cultural significance in Tibet. This study explores the ethnobotanical uses of plants used to make wooden bowls to understand their sustainability, cultural significance, and current status of related traditional knowledge in Gyirong Town, which is one of the most famous places for wooden bowl making.

MATERIALS AND METHODS

Between 2019 and 2021, key informant interviews, semi-structured interviews, and participatory observations were used to conduct ethnobotanical field surveys in Gyirong Valley. The field work was performed with the assistance of local guides. In this study, we utilized a use-report (UR) to reflect the number of mentions of a species by locals.

RESULTS

Our results show that 16 different plants are used during the wooden bowl making process, of which nine are used as raw materials, three for dyeing, and four for varnishing. Although communities rely heavily on these plants, good management and collection methods were observed. We also documented the use of Fallopia denticulata as a red dye and four species of Impatiens as wood varnishes for the first time.

CONCLUSION

The wooden bowl craftsmen and their housewives have a wealth of traditional knowledge of using plants to make wooden bowls in Gyirong Town. And the wooden bowls are now also offering benefits to the locals as well. The government and local people are committed to the protection and development of traditional knowledge related to wooden bowls, and this knowledge maintains a healthy degree of vitality. This research can provide insights into the vitality of traditional handicrafts that are facing challenges and promote their protection.

Ethnobotanical study on plants used to dye traditional costumes by the Baiku Yao nationality of China

BACKGROUND

The Baiku Yao is a branch of the Yao nationality in China. The unique dying process of traditional clothing employed by these people has distinct national characteristics, a profound impact on the production and life of local people, and important research value. For this reason, it is important to investigate and document the dyeing plants and the traditional knowledge involved in the dyeing of Baku Yao traditional clothing.

METHODOLOGY

Information on dyeing plants was obtained using the free-list method and interviews with 61 Baiku Yao informants in Guangxi and Guizhou from January 2020 to August 2021. Based on the free-list method, we evaluated and screened out important plants by calculating the cognitive salience value of each plant.

RESULTS

The results showed that the people of Baiku Yao have accumulated rich traditional knowledge of dyeing plants and long-term dyeing and other processes. We collected 23 species and recorded the related traditional knowledge, such as the Baiku Yao name, life form, habitat, part(s) used, application type, usage, and area used. The utilization of dyeing plants has a strong relationship with ethnic culture. The Baiku Yao uses unique anti-dyeing material (Ailanthus vilmoriniana) in the cotton dyeing process, they call it "the mother tree". As well as, the results also showed that 15 plants (65.2%) have medicinal value and can be used to treat 18 aliments, and wild plants play a very important role in the life of the Baiku Yao.

CONCLUSION

These plants not only meet the color needs of the Baiku Yao people but also have health care effects, aligning with the trends toward green dyeing and the health contentiousness of modern people. This study provides a reference for the inheritance and development of Baiku Yao traditional clothing dyeing culture, will aid the identification of new natural, safe and healthy textile dyes, and is of positive significance in promoting regional economic development, national cultural inheritance, and biodiversity protection.

Ethnobotanical investigation of medicinal plants used in Lingchuan county, Shanxi, China

Abstract Medicinal plants are the primary sources of healthcare among the people of developing countries in villages and local towns. Documenting and reporting the traditional knowledge of medicinal plants may contribute to pharmaceutical research development. For this reason, we present our findings on ethnomedicinal plants from Lingchuan County, Shanxi, China, an unexplored area rich in medicinal plant resources. Information of ethnomedicinal plants were collected through questionnaire/semi-structured interviews from 180 informants, including traditional healers. Field surveys were conducted in 53 villages of Lingchuan County from 2017 to 2018. Informed consent was obtained from each participant before conducting the interview process. Quantitative analysis was performed for each recorded species, such as Relative Frequency Citation (RFC), Use Value (UV), and Factor of Informant Consensus (FIC). Diseases were categorized into twelve groups. A total 138 species of medicinal plants were recorded, belonging to 123 genera of 58 families. Asteraceae was the dominant plant family with 19 species, followed by Rosaceae and Fabaceae. Herbs were dominant among plant life-forms with 96 species, followed by shrubs and trees (15 species each). Roots were the most commonly used plant parts with 58 species, followed by whole plants and fruits (28 species each). Most plant species were reported non-toxic (84, 60%), followed by unknown toxicity (35, 25%), poisonous, and less toxic (19, 14%). Quantitative analysis revealed that Forsythia suspensa was with higher (0.33) RFC value, and Scutellaria baicalensis was recorded with a higher (0.91) UV. Treated diseases were categorized in 12 groups and evaluated by their FIC value, in which gynecological diseases have higher (0.93) FIC value followed by urinary system diseases. Most medicinal plants are used to clear away heat and relieve the surface. The present study revealed that local people of Lingchuan County confidently use ethnomedicinal plants for their healthcare needs. The higher indices value of a plant species resulted from quantitative analysis warrants further investigation, which may possess valuable phytochemical compounds that may result in new drugs for treating various human disorders.

Antioxidant and tyrosinase inhibitory activities of traditional fermented Rosa from Dali Bai communities, Northwest Yunnan, China

Traditional fermented Rosa (TFR) is a typical food and medical product among the Dali Bai people, and its popularity is growing. A few studies have looked into TFR's medicinal advantages, linked germplasm resources, traditional processing procedures, and functional food qualities. Our goal was to look into Rosa's traditional processing, examine the dominant strains in TFR, and prove how these strains affected antioxidant and tyrosinase inhibitory activities. We used a snowball selection strategy to pick 371 informants for a semi-structured interview, supplemented with direct observations and sample collection. A microbial strain was isolated and identified from a TFR sample collected in the field. We synthesized TFR in the lab using the traditional way. Both of 2, 2-diphenyl-1 picrylhydrazyl (DPPH) free radical scavenging and tyrosinase inhibitory properties of the fermented solution of Rosa 'Dianhong' have been tested in this study. Altogether 15 species belonging to the genus Rosa, which are utilized in herbal medicine and fermented foods. Rosa 'Dianhong' was the Bai community's principal species with considerable cultural value and consumption. Raw Rosa petals included 15 major flavonoids and phenols, which were identified as TFR's active components. TFR-1 was discovered to be the dominating microbial strain in TFR, increasing total phenolic and flavonoid content in the fermented solution of Rosa 'Dianhong' by 0.45 mg GAE/ml and 0.60 mg RE/ml, respectively, after 30 days. TFR-1 also exhibited promising activity in terms of DPPH free radical scavenging and tyrosinase inhibition. TFR showed potent antioxidant and free-radical scavenger properties and is beneficial in skincare and nutrition, according to the findings. TFR's medicinal and edible properties suggest that it could be used as a cosmetic or nutraceutical product.

Reusing wasteroot of Rubia wallichiana dyeing from Monpa of Tibet in China

Humans have dyed textiles and leather, colored food, and paint body parts using natural dyes throughout history. Natural dyes have suffered drastically due to recent socioeconomic changes and replacement with synthetic dye in the textile industry. Hence, it is urgent to study indigenous dye plants and dyeing craft in local communities to protect these resources' potential ecological, economic, and cultural values. In 11 Monpa villages of Mêdog County, South-east Tibet, China, we conducted field research to record the indigenous method of cloth dyeing using madder dye. An aqueous extract of the root of Rubia wallichiana is a traditional madder dye. In this study, we used traditional dye and ethyl alcohol extract of the residue of aqueous extract. Two fabrics were dyed with the extractions in the presence of one of the metallic mordants or biomordants. Pigment compounds from aqueous extraction of madder and ethyl alcohol extraction of recycled madder were evaluated using Phytochemical, UV-visible spectroscopy, and FTIR test. We carried out One-way ANOVA and Duncan's new multiple range method to analyze different dying approaches and conditions. The dyed fabrics were evaluated by indicators of color strength and fastness, including washing, rubbing, and perspiration. The findings revealed the potentiality of biomordants to improve the dyeing properties of madder. The dyeing properties of recycled madder were marginally better than traditional madder. The results revealed the feasibility of enhancing the dyeing property and reuse of the residue from madder dyeing. The improved dyeing and reuse of residue can improve local ecological, economic benefits, and cultural heritage while applying research findings for the subsequent commercialization of plant dyes.

Strobilanthes cusia (Nees) Kuntze, a multifunctional traditional Chinese medicinal plant, and its herbal medicines: A comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Strobilanthes cusia (Nees) Kuntze (SCK, Malan), a traditional Chinese medicinal plant, has long applied to detoxification, defervescence, detumescence and antiphlogosis. "Southern Banlangen" (Rhizoma et Radix Baphicacanthis Cusiae, RRBC), root and rhizome of SCK, is widely used for treatment of many epidemic diseases. Malanye (Southern Daqingye), stem and leaf of SCK, is an antipyretic-alexipharmic drug frequently-used in southern China. Qingdai (Indigo Naturalis, IN), a processed product of SCK, is always applied to dermatoses in the folk.

AIM OF THE REVIEW

In order to elucidate the historical uses, recent advances and pharmaceutical prospects of SCK, we summarized roundly in aspects of history, processing method, chemical constitution, quality control, pharmacological activity and toxicity. Some deficiencies in current studies and research directions in the future are also discussed. This is the first comprehensive review of SCK and its herbal medicines, which may be of some help for further research.

METHODOLOGY

Comprehensive analysis was conducted on the basis of academic papers, pharmaceutical monographs, ancient medicinal works, and drug standards of China. All available information on SCK and its herbal medicines was collected by using the keywords such as "Strobilanthes cusia", "Southern Banlangen", "indirubin", "tryptanthrin" through different electronic databases including NCBI Pubmed, Google Scholar, Chinese National Knowledge Infrastructure and so on. Pharmacopoeia of China and some ancient works were obtained from National Digital Library of China.

RESULT

Medicinal uses of SCK were already described by famous ancient researchers. Because of vague description, plant species in some works cannot be confirmed. Literature demonstrated that multiple components including total 36 alkaloids and 35 glycosides, the main bioactive components of SCK, were found in SCK and its herbal medicines. Modern studies indicated that SCK and some of its components had multiple pharmacological effects including resistance to cancer, remission of inflammation, suppression of microorganisms, relief of dermatoses, and so on. However, studies on pharmacology, pharmacokinetics, and quality control are still not enough.

CONCLUSION

A number of reports suggested that SCK and its processed medicines could be promising drug candidates for multiple diseases especially promyelocytic leukemia, ulcerative colitis (UC) and psoriasis. However, bioactive activities of most components, especially glycosides should still be explored further. It is crucial to elucidate the in-depth molecular mechanisms, and pharmacokinetic characteristics of main components in those herbal medicines. Moreover, to ensure the effectiveness of clinical medication, future studies should undoubtedly give the priority to clarifying the effective compositions of SCK, and then a measurement standard of those indicators should be protocolled to establish a comprehensive quality evaluation mode.