It is important to raise awareness regarding rice's nutritional quality and health benefits in terms of enhancing rice consumption in people's daily diets. This study evaluated the proximate components and phytochemical profiles of 11 Thai rice bran varieties, 4 non-colored rice brans and 7 colored rice brans, collected from the same agricultural fields. The chemical composition (ash, fat, proteins, fiber, and gross energy) was determined using proximate analysis methods. High-performance liquid chromatography was used to analyze the γ-oryzanol, tocopherols, and anthocyanins, while gas chromatography mass spectrometry determined the free fatty compounds. The phenolic profile was determined using liquid chromatography-mass spectrometry. The results showed great variations in each parameter of the nutritional and bioactive components among different rice bran varieties. Statistical analysis was also performed correlating the results obtained from PCA to categorize the samples by their nutritional characteristics into three main groups: group A with a high content of protein and fiber, group B with a high content of fat and gross energy, and group C with low fat and energy values but high amounts of functional, active components, particularly γ-oryzanol. Anthocyanins were detected in only one sample of colored rice bran. The major free fatty acids found in rice bran samples were oleic, linoleic, and palmitic acids. Systematic assessment of the concentration of these compounds gained from this study would be helpful to the industrial sector for selecting phytochemical-rich varieties as a value-added component in nutritional products.

The natural forests of Northern Thailand are the mother source of many utilisable natural products because of their diverse flora and fauna. Northern Thai people have learned to utilise plants, in particular those of plants with cleansing properties, since the beginning of time. Several local species of detergent plants in Thailand are traditionally used by the locals and indigenous people. However, these plants may become extinct because their habitats have been replaced by industrial agriculture, and their uses have been replaced by chemically synthesised detergents. Researchers need to study and communicate the biology, phytochemistry, and the importance of these plants to conserve natural biodiversity of Northern Thailand. Of many utilisable detergent phytochemicals, natural saponins are known as bio-based surfactant and foaming agents. Their physiochemical and biological properties feature structural diversity, which leads to many industrial applications. In this review, we explained the term “detergent” from the physiological mechanism perspective and the detergent effects of saponins. We also compiled a list of Thai local plants with cleansing properties focusing on the saponin-containing plants. Future studies should investigate information relative to plant environment, ethnobotanical data, and the bioactive compound content of these plants. The knowledge acquired from this study will promote the maintenance of the local biodiversity and the conservation of the detergent plant species found in Thailand.

Graphical abstract

The natural forests of Northern Thailand are the mother source of many utilisable natural products because of their diverse flora and fauna. Among many plant species found within Northern Thai forests, detergent plants are known for its distinctive cleansing properties. Several local species of detergent plants in Thailand are traditionally used by the locals and indigenous people. However, these plants may become extinct because their habitats have been replaced by industrial agriculture, and their uses have been replaced by chemically synthesised detergents. Researchers need to study and communicate the biology, phytochemistry, and the importance of these plants to conserve natural biodiversity of Northern Thailand. Of many utilisable detergent phytochemicals, natural saponins are known as bio-surfactant and foaming agents. Their physiochemical and biological properties feature structural diversity, which leads to many industrial applications.  In this review, we explained the term “detergent” from the physiological mechanism perspective and the detergent effects of saponin.  We also compiled a list of Thai local plants with cleansing properties focusing on the saponin-containing plants. Future studies should investigate information relative to plant environment, ethnobotanical data and bioactive compound content of these plants. The knowledge acquired from this study will promote the maintenance of the local biodiversity and the conservation of the detergent plant species found in Thailand.

In this research, we assessed the detergency properties along with chemical characteristic of the surfactant extracts from the most frequently cited detergent plants in Northern Thailand, namely, Sapindus rarak, Acacia concinna, and Litsea glutinosa. Moreover, as to provide the sustainable option for production of such valuable ingredients, plant tissue culture (PTC) as alternative method for industrial metabolite cultivation was also proposed herein. The results illustrated that detergent plant extracts showed moderate in foaming and detergency abilities compared with those of synthetic surfactant. The phytochemical analysis illustrated the positive detection of saponins in L. glutinosa plant extracts. The highest callus formation was found in L. glutinosa explant cultured with MS medium supplemented with 2.0 mg/L Indole-3-acetic acid (IAA). The callus extract was chemical elucidated using chromatography, which illustrated the presence of saponin similar to those from the crude leaf and Quillaja saponin extracts. Compact mass spectrometry confirmed that the surfactant was of the steroidal diagnostic type.