Traditional Knowledge Of Medicinal Plants Research Articles

Indigenous Knowledge and Herbal Medicine: Exploring the Ethnobotany of the Karo Tiganderket Tribe in Indonesia

This ethnobotanical study investigates the traditional use of medicinal plants in Tiganderket Village, Karo Regency, Indonesia, to document local plants' diversity, uses, and preparation methods for medicinal purposes. Utilizing a quantitative descriptive approach, data were gathered from 30 informants, including traditional healers and residents. The study identified 92 plant species from 44 families, with the Zingiberaceae family being the most dominant. Frequently used plants, such as Piper betle (belo) and Zingiber officinale (ginger), were primarily employed to treat common ailments like fever, boils, and joint pain. Boiling (74%) was the most common method of plant preparation, and leaves (50%) were the most frequently used plant parts. The Relative Frequency of Citation (RFC) revealed Acorus calamus and Curcuma longa as the most cited species. At the same time, 40 of 66 recorded diseases showed high Informant Consensus Factor (ICF) values, reflecting shared knowledge of plant use. This study highlights the rich preservation of traditional medicinal plant knowledge in Tiganderket Village, which continues to play a crucial role in local healthcare practices.

Ethnobotanical knowledge of plant species of the North-East of Morocco, with three provinces as a case study: Al Hoceima, Nador, and Jerada.

This study focuses on taxa found in the Northeastern part of Morocco and cited in the book “Al Jam’ li-Mufradat al-Adwiya wa’l-Aghdiya (The Book of Simple Drugs) by Ibn Al Baytar. The main objective of this study is to determine whether the taxa on our list are recognized by the populations in the three provinces of Northeastern Morocco, as well as to collect information about their traditional uses (medicinal or non-medicinal), their modes of preparation and administration, the plant parts used. All the data have been collected through conducting an open-ended, semi-structured interviews with randomly selected individuals. The informant consensus factor (FIC) was calculated to identify the level of agreement among informants regarding the use of medicinal plants for specific disease groups. During these ethnobotanical surveys, 1,177 persons were interviewed. We were able to record a total of 241 taxa belonging to 66 families with 1,264 uses mentioned in the three provinces. The results obtained confront us with the idea that there is a decline of autochthonous knowledge. They reveal that 32.12% of the local population considers itself ignorant of the uses of plants to cure illness, and that 66.78% prefer modern medicine despite possessing some knowledge of traditional medicinal plants. However, 790 medicinal uses recorded were classified according to the WHO’s international Classification of diseases (ICPC-2, International Classification of Primary Care), and 474 other uses were recorded, along with the transcription of new vernacular names for 107 taxa. This confirms the importance of ethnobotanical studies as it plays an important role in preserving the reservoir of indigenous knowledge from being lost over time.

Ethnobotanical, ethnopharmacological, socioeconomic and floristic studies of aromatic and medicinal plants from Boulemane region in Morocco

These studies were conducted to uncover the potential and traditional knowledge of aromatic and medicinal plants (AMP) in the Boulemane province of the Middle Atlas, an area previously unexplored. The objectives were to inventory and identify AMP used in the region’s traditional medicine, gather extensive information from locals and professionals on their usage and exploitation, and identify the most promising species for further studies, to be highlighted in future publications. The floristic study enabled the identification of 71 families out of 155 existing in Morocco, comprising 313 genera and 618 species and subspecies, which represent 11% of the global Moroccan floristic richness. Additionally, 84 taxa from 20 families are endemic with 78% being exclusive to Morocco. The ethnopharmacological study revealed that 88.47% of the informants use AMP for therapeutic purposes in 58.21% of the cases. A catalog of traditional practices was compiled, documenting 79 species across 38 families. Rosemary, sagebrush, pennyroyal, thyme, berber cedar, lavender sage, and clubroot were the most frequently cited species, mainly used to treat stomach and respiratory problems. However, only 17.6% of the population exploits this wealth through the creation of cooperatives and/or associations. This study assessed the role of AMP in fostering sustainable development in the region. The evaluation was based on a series of studies, with particular emphasis on the ethnopharmacological aspect. The latter has facilitated the promotion of awareness of sustainable usage practices and the training of professionals to implement these practices while ensuring the conservation of botanical resources against over-exploitation.

Traditional knowledge and biodiversity of medicinal plants in the Taounate region for treating human diseases: An ethnobotanical perspective

Traditional knowledge and biodiversity of medicinal plants in the Taounate region for treating human diseases: An ethnobotanical perspective

Exploring Ethnobotany in the Catalan Linguistic Area: Traditional Plant-Based Knowledge for Addressing Gastrointestinal, Metabolic, and Nutritional Disorders.

Ethnobotanical research in the Catalan linguistic area (CLA) is crucial due to the persistence of traditional medicinal plant knowledge. Gastrointestinal, metabolic, and nutritional disorders are major global health issues requiring effective treatments. This study aimed to analyze plants used for these disorders in the CLA, compare the findings with phytotherapy literature, and examine correlations between plant use in humans and animals. Data were sourced from the database of the research group of Catalan ethnobotany at the University of Barcelona and the Botanic Institute of Barcelona, representing a collection of ethnobotanical studies. A total of 630 plant taxa were examined, with 15,252 use reports (UR) provided by 2301 informants. Gastrointestinal disorders were the focus, comprising 94.24% of the UR. The high informant consensus factor (0.96) indicated strong reliability of the results. The most often reported species were Matricaria recutita (5.97%), Thymus vulgaris (5.12%), and Lippia triphylla (4.90%). Lamiaceae (19.86%), Asteraceae (18.78%), and Rosaceae (5.55%) were the top botanical families. The main uses were digestive (17.62%), intestinal anti-inflammatory (15.68%), and antidiarrheal (8.91%). The main part of the plant used was the aerial part (33.22%). Tisane (69.25%) was the most cited pharmaceutical form. Traditional uses were confirmed by pharmacological literature in 57.59% of cases. This work highlights the potential of medicinal plants for treating gastrointestinal, metabolic, and nutritional disorders in the CLA. Further research is possible in other territories, as well as in the phytochemical and medicinal aspects of the plants recorded.

Usage and preservation of Mizo traditional medicine by the people of Chungtlang Village, Mamit District, Mizoram.

Diversity, flexibility, easy accessibility, broad continuing acceptance in developing countries and increasing popularity in developed countries, relative low cost, low levels of technological input, relative low side effects, and growing economic importance are some of the positive features of traditional medicine. In rural India, traditional medicine continues to be the only available form of care. Many communities continue to treat patients using their old methods, unaffected by contemporary medical advancements. Due to their accessibility, affordability, and ease of use, tribal tribes prefer to utilize and consult their own traditional healers. These are likewise thought to be highly effective and without any adverse effects. This paper aims to identify various traditional medicines used for treating illness and infirmities, by taking accounts from the residents of Chungtlang village, Mamit District, Mizoram. The objective here lies in discovering traditional knowledge of medicinal plants and their uses for various infirmities.

Growing Native Medicinal Plants in Amajari – RR

The aim of this work was to set up a permanent production area for native and exotic medicinal plants, especially those at risk of extinction. The species grown were herbs, shrubs and medicinal trees of various species, both native and exotic. Nineteen species were cultivated by 20 students from the Ovídio Dias de Souza State School who took part in the practicals at the school. It was observed that the fact that the majority of the students reported a preference for using medicinal plants, perhaps due to the lack of any other way of maintaining or recovering their health, is, in a way, a positive aspect, because as well as strengthening traditional practices regarding the use and traditional knowledge of medicinal plants, it is an activity that values the preservation of the local flora.

Medicinal flora of the baiku yao people — An ethnobotanical documentation in South China

BackgroundThis study explores the medicinal plant knowledge of the Baiku Yao, a unique ethnic group in China. Despite existing research on their ethnobotanical practices, a comprehensive understanding of their medicinal flora remains lacking. This study aims to document and analyze the species distribution, utilization, and traditional knowledge of medicinal plants used by Baiku Yao.MethodsEthnobotanical surveys were conducted in various Baiku Yao villages across different seasons from 2019 to 2023. Informants were interviewed, and plant specimens were collected and identified. Statistical analyses, including the Relative Frequency of Citation (RFC), were employed to understand plant importance in Baiku Yao culture.ResultsIn an ethnobotanical survey conducted in the Baiku Yao region, 434 medicinal plant species were documented, highlighting significant ethnobotanical diversity and a deep cultural integration of traditional medicinal practices. The study revealed pronounced geographical variations in plant knowledge among villages, with a notable reliance on wild plants, as 85.48% were sourced from the wild, reflecting unique local ethnobotanical knowledge. Predominantly herbs and shrubs were used due to their accessibility and abundance in the local environment. High Relative Frequency of Citation (RFC) values for certain species underscored their importance for local health needs and additional economic value. The utilization of various plant parts, particularly whole plants, roots, and leaves, indicates a holistic approach to medicinal applications, adapted to combat prevalent health issues such as skin and infectious diseases. The study also uncovered the Baiku Yao’s cultural practices for countering “Gu” afflictions—a range of pathogenic conditions—with 18 diverse antidote plants used for skin, digestive, and musculoskeletal disorders. The study underscores the imperative of preserving this rich medicinal heritage through innovative models that engage youth and leverage new media, ensuring the inheritance and evolution of Baiku Yao’s traditional knowledge.ConclusionsBaiku Yao’s medicinal plant use reflects a deep, culturally ingrained knowledge, closely tied to local ecology. The study highlights the importance of preserving this unique ethnobotanical heritage and suggests interdisciplinary approaches for future research.

Exploring the power of data mining for uncovering traditional medicinal plant knowledge: A case study in Shahrbabak, Iran.

The present study recorded indigenous knowledge of medicinal plants in Shahrbabak, Iran. We described a method using data mining algorithms to predict medicinal plants' mode of application. Twenty-oneindividuals aged 28 to 81 were interviewed. Firstly, data were collected and analyzed based on quantitative indices such as the informant consensus factor (ICF), the cultural importance index (CI), and the relative frequency of citation (RFC). Secondly, the data was classified by support vector machines, J48 decision trees, neural networks, and logistic regression. So, 141 medicinal plants from 43 botanical families were documented. Lamiaceae, with 18 species, was the dominant family among plants, and plant leaves were most frequently used for medicinal purposes. The decoction was the most commonly used preparation method (56%), and therophytes were the most dominant (48.93%) among plants. Regarding the RFC index, the most important species are Adiantum capillus-veneris L. and Plantago ovata Forssk., while Artemisia auseri Boiss. ranked first based on the CI index. The ICF index demonstrated that metabolic disorders are the most common problems among plants in the Shahrbabak region. Finally, the J48 decision tree algorithm consistently outperforms other methods, achieving 95% accuracy in 10-fold cross-validation and 70-30 data split scenarios. The developed model detects with maximum accuracy how to consume medicinal plants.

Traditional knowledge of medicinal and aromatic plants after the demographic changes in Bosnia and Herzegovina

Traditional knowledge of medicinal and aromatic plants after the demographic changes in Bosnia and Herzegovina

Ethnobotanical study and vulnerability of medicinal plants used against the symptoms of COVID-19 in the Lomié subdivision, East Region of Cameroon

Science has advanced to the point that traditional medicine is now a useful instrument for treating a wide range of human ailments. Indigenous peoples and local communities (IPLCs) do not, however, have access to the contemporary healthcare system. As a result, they turn to biological resources, which are the only readily available and accessible means of treating diseases like COVID-19 and flu outbreaks. In response to worldwide illnesses, this study aligns with the perspectives of traditional knowledge of biological resources, particularly therapeutic plants. Therefore, this study was aimed to document the use of the potential of medicinal plants by IPLCs in the Lomié subdivision to manage COVID-19 symptoms. In four villages in the Lomié subdivision Ekom, Payo, Eschiambor, and Kongo, ethnobotanical surveys, including semi-structured interviews on traditional usage of plants against Covid-19 symptoms, were carried out with 80 participants in order to meet all of the study specific objectives. For every species, a vulnerability index was established in order to evaluate the species fragility. To analyze the data, both descriptive and inferential statistics were applied. The findings show that the respondents are well aware of the symptoms of the COVID-19 and that gave them the ability to provide timely and efficient responses. The survey identified 43 species from 39 genera grouped in 28 families were used to treat COVID-19 symptoms, with bark being the most commonly used plant part (43.8%). Decoction was the most frequently used method of preparation (50%), and oral administration was the main route of administration (56.3%). Most of the plant species were harvested from secondary forests (44.2%), of which trees formed 48.8%. A total of 30 species were recorded to be vulnerable, with Entandrophragma cylindricum (Sprague) Sprague, Milicia excelsa (Welw.) Benth, Myrianthus arboreus P. Beauv., and Trichoscypha aborea (A. Chev.) A. Chev being the most vulnerable, with vulnerability index of 2.4. The results showed a strong non-causal relationship between vulnerability and the continuous and discontinuous explanatory parameters. The susceptibility of medicinal plants used to treat COVID-19 symptoms and the explanatory parameters had a statistically significant causal association, according to the binomial logistic regression model. In light of novel diseases like COVID-19, this study finds that traditional knowledge of medicinal plants is still widely held, especially among the indigenous and local population. It can also be very beneficial in the development of new medications for a variety of illnesses.

Ethnobotanical study of traditional medicinal plants used by the local Gamo people in Boreda Abaya District, Gamo Zone, southern Ethiopia

BackgroundMedicinal plants have been used for centuries and are still relied upon by over 80% of the Ethiopian population. The people of Gamo, southern Ethiopia, have a rich cultural and traditional lifestyle with a long history of using plant resources for various uses including traditional herbal medicine. However, their traditional knowledge of traditional medicinal plants in Boreda Abaya District has not been explored Ethnobotanically yet, despite preserving diverse indigenous traditional medicinal plants. Hence, the study aimed to document and analyze traditional medicinal plants and associated traditional knowledge and practices used by local people.Materials and methodsQuantitative ethnobotanical data were collected via semi-structured interviews, face-to-face conversations, group discussions, and guided field trips between September 2022 and February 2023. In total, 92 informants participated, of which 25 were key informants. Quantitative data indices (informant consensus factor—ICF—and use report—Ur) were computed by MS Excel spreadsheet software. Scientific names of medicinal plants were checked via World Flora Online.ResultsIn the present study, we recorded 188 traditional medicinal plant species belonging to 163 genera and 73 plant families. Lamiaceae (16 species), Asteraceae (16 species), Fabaceae (11 species), and Euphorbiaceae (8 species) contributed highest number of species and were found to be predominant family in the area. Leaves and seeds were most frequently used plant parts, and pounding (46%) was the main method to prepare remedies. The sudden sickness disease category scored the highest consensus (ICF: 0.35), followed by blood and circulatory-related disease categories (ICF: 0.33). The highest number of plant taxa (61 species) used to treat dermal disease has a 71-use report score, while fewer plant taxa (21 species) were utilized to treat genitourinary system-related disease category, having 25 use reports. Ocimum lamiifolium (Ur:56) and Moringa stenopetala (Ur:51) are widely used species and received highest use report value.ConclusionGamo people possess extensive traditional knowledge of ethnomedicine. The region's vegetation hosts diverse medicinal species, but deforestation, agriculture, and droughts threaten them. Local conservation practices require scientific support, prioritizing species having higher use reports (Ur), and in-depth investigations of promising species for drug development are essential.

Assessment of traditional knowledge of medicinal plants practiced by rural communities residing around Musk Deer National Park, Kashmir Himalaya, Pakistan

Assessment of traditional knowledge of medicinal plants practiced by rural communities residing around Musk Deer National Park, Kashmir Himalaya, Pakistan

Ethnobotanical study on medicinal plants used by the Yi people in Xiaoliangshan, Yunnan Province, SW China

Ethnopharmacological relevanceThe Yi people in the Xiaoliangshan region in southwest China have a unique practice of combining ritual treatment and traditional medicine to care for patients. Despite increasing urbanization in the area, they have managed to preserve their distinctive lifestyle and extensive knowledge of traditional medicinal plants, setting them apart from other regions. However, there is a lack of systematic documentation on the knowledge of traditional medicinal plants used by the Yi people in Xiaoliangshan. Aim of the studyThis research aims to achieve the following objectives: 1. Document the diversity of medicinal plants used by the Yi people and explore their therapeutic usages. 2. Evaluate and analyze the main types of diseases with a high incidence in the local area and identify the types of medicinal plants used to treat these diseases. 3. Explore the underlying geographical and human factors influencing both disease prevalence and medicinal plant usage. MethodsEthnobotanical research methods were used to record and analyze the medicinal plants used by the Yi in Xiaoliangshan. Experts identified all plant specimens collected during ethnobotanical field surveys. The types of diseases treated by medicinal plants were classified according to the International Classification of Primary Care -2nd. ResultsA total of 125 medicinal plants were recorded after interviewing 193 participants. Of the medicinal plants identified, those with over 100 use reports were Paris polyphylla (202 use reports), Taxillus sutchuenensis (183), Artemisia indica (149), and Papaver somniferum (113). A total of 14 disease categories were recorded, with those related to the following categories having higher Informant Consensus factor values (ICF ≥0.85): Pregnancy, Childbearing, Family Planning, General and Unspecified, Urological, Respiratory, Musculoskeletal, and Skin. The highest quantity of medicinal plants is utilized to improve specific diseases and health problems, namely those related to Digestion, Skin, and Musculoskeletal. Fewer plant species were utilized for diseases or health issues associated with Eyes, Psychological, or Pregnancy, Childbearing, and Family Planning. The use reports from the informants also revealed how some medicinal plants are used to treat a variety of diseases or health issues. For instance, Malva pusilla is used for inducing abortion, treating postpartum hemorrhage, and joint sprains; Artemisia indica is used for treating malaria; Argentina lineata is used to remedy tuberculosis and malaria. Taxillus sutchuenensis is used for dealing with cold, pneumonia, and other ailments. ConclusionsThe Yi people in Xiaoliangshan have a rich knowledge of traditional medicinal plants. Decoction and wine brewing are the most common processing methods used for these plants, which are utilized to treat a wide range of diseases. The characteristics of the medicinal use of the Yi people reflects the alpine mountainous environment in which they live, and their medical practices are closely related to traditional healing culture. This study enhances our understanding of the Yi traditional medicine via documentation and offers a valuable reference for future research and the development of new drugs.

The potential of Ethiopian medicinal plants to treat emergent viral diseases.

Ethiopians have deep-rooted traditions of using plants to treat ailments affecting humans and domesticated animals. Approximately 80% of the population continues to rely on traditional medicine, including for the prevention and treatment of viral diseases. Many antiviral plants are available to and widely used by communities in areas where access to conventional healthcare systems is limited. In some cases, pharmacological studies also confirm the potent antiviral properties of Ethiopian plants. Building on traditional knowledge of medicinal plants and testing their antiviral properties may help to expand options to address the global pandemic of COVID-19 including its recently isolated virulent variants and prepare for similar outbreaks in the future. Here, we provide an ethnobotanical and pharmacological inventory of Ethiopian medicinal plants that might contribute to the prevention and treatment of viral diseases. We identified 387 species, about 6% of Ethiopia's known flora, for which records of use by local communities and traditional herbalists have been documented for the treatment of viral diseases. We provide a framework for further investigation and development of this vital resource much anticipated to help combat emergent viral diseases along with existing ones in Ethiopia and elsewhere.

Traditional Knowledge of Medicinal Plants Used for Cosmetic Purposes in The Fez-Meknes Region

Traditional Knowledge of Medicinal Plants Used for Cosmetic Purposes in The Fez-Meknes Region

Ethnobotanical study of medicinal plants of lake Abaya basin, southern Ethiopia

IntroductionEthnobotanical study was conducted in lake Abaya basin, southern Ethiopia. The study aimed at documenting indigenous and local knowledge and use of traditional medicinal plants for treating human and livestock ailments. MethodsA survey was conducted among purposively selected traditional healers and randomly selected herbal medicine practitioners of the local communities. Guided field observations, semi-structured interview, group discussions and market survey were used for ethnobotanical data collection. Preference and direct matrix rankings including descriptive and inferential statistics were used to analyse the data. ResultsSeventy-one medicinal plant species belonging to 64 genera and 36 families were used as remedies for human and livestock ailments. Among these, 51 were reported for human, 13 for livestock ailment treatments and seven for both. Most of them were collected from the wild. The most frequently used plant parts were leaves followed by roots. The largest numbers of remedies were used to treat abdominal disorders. The major routes of administration include oral, dermal and nasal. Leucas abyssinica ranked first and most effective to cure abdominal disorder followed by Lepidium sativum and Stephania abyssinica. Moringa stenopetala was most preferred multipurpose plant by local people. Agricultural expansion was the major threatening factor followed by firewood consumption. ConclusionsTraditional healers apply diversified traditional medicinal plants for healthcare of the community and domestic animals. However, traditional medicinal plants and the associated indigenous knowledge of local community were under threat. Thus, public awareness and community-based management need to be encouraged to maintain indigenous ethnomedicinal knowledge of the study area.

KEPRAKTISAN BUKU ILMIAH POPULER ETNOBOTANI TUMBUHAN OBAT DI KOTA TIDORE KEPULAUAN

The importance of traditional knowledge about medicinal plants needs to be documented in the form of references through scientific research so that it is not lost by cultural modernization so that it can be preserved by the next generation. Written references about traditional knowledge of medicinal plants can be written in the form of books, one of which is popular scientific books. The purpose of this research is to develop a popular scientific book on medicinal plants in the city of Tidore Islands. The type of research used is research and development with the ADDIE development model consisting of 5 stages, namely analysis, design, development, implementation, evaluation. The research subjects consisted of 12 students in the 3rd semester of the Biology study program, 3 students in the 5th semester of the Biology study program, and 4 people from the community who represented the city of Tidore. The data collection technique uses a validation questionnaire for experts and small-scale trials. The results of the development of popular scientific books show that the average results of the validation and testing are in the appropriate category for use with good predicates in accordance with the table of eligibility criteria and product revisions.

Exploration of ethno-medicinal herbs and their practices by indigenous people of Achanakmar regions of Chhattisgarh State, India

The study was performed in the Achanakmar regions of Chhattisgarh state, India. At the study site, a total of 54 herbaceous medicinal plants belonging to 30 families were documented. Between March 2020 and March 2022, intensive field surveys were conducted in the research areas. Native knowledge of wild medicinal plants was obtained on field trips through questionnaires, discussions, and in-person interviews. In accordance with their correct nomenclature, plants were organized according to their botanical name, family, common name, parts used and diseases treated. The Zingiberaceae family was the most prevalent in the current study, accounting for 5 plant species used by the region's indigenous people. This was followed by the Amaranthaceae, Acanthaceae, Fabaceae, Asteraceae and Lamiaceae families, each representing 3 species of plants. For a longer period of time, the rural residents of the Achanakmar region have used native flora for primary healthcare and the treatment of various diseases. However, there was little information about traditional knowledge of medicinal plants documented. Rural Achanakmar people asserted that younger generations are less interested in traditional knowledge of medicinal herbs due to societal development. Therefore, it is crucial to document ethnomedicinal plants before they are no longer available and go extinct. In order to effectively conserve plants and traditional knowledge for the future, this ethnobotanical database will be helpful to scientists, naturalists, planners, policymakers, and chemists.

Ethnobotanical Study of Plants Used in the Management of Benign Prostate Hyperplasia in Ilorin, Nigeria

Background: Benign Prostate Hyperplasia (BPH) is a prevalent illness in older men. It is a condition where the prostate becomes enlarged and blocks the ease of urine passage out of the bladder. Around 50% of the male population develops symptoms of BPH around 51- 60 years of age. Current therapeutic management options come with undesirable side effects like weight gain, dizziness, and impotence, hence, the need to source for safer alternatives initiated by the acquisition, recording, and preservation of traditional knowledge of medicinal plants.
 Objective: This study aims to preserve indigenous knowledge by documenting medicinal herbs in use as therapy for BPH.
 Materials & method: Ethnobotanical survey was carried out in the study areas through interviews using a semistructured questionnaire. Respondents included elderly members of the communities, herbalists, and practitioners of traditional medicine. Quantitative ethnobotany index (Use value index) and descriptive statistics were used to analyse data.
 Results: 50 respondents were interviewed, 64% were Herb sellers, 22% TMPs, Others 14%. 37 plants belonging to 24 plant families were mentioned in the survey. Methods of preparation of recipes mentioned includes: maceration (37%), decoctions (52%), juice (7%), infusions and paste/powder (4%). Method of administration were majorly oral route. The plant family Fabaceae (19%) had the highest representation. This was followed by the families Annonaceae (8%), Euphorbiaceae (6%), Curcubitaceae, Menispermaceae, Combretaceae, Apocynaceae and Rutaceae with 5% each. Other plant families represented 42% of the total number of plants mentioned.
 Conclusion: The study areas are endowed with abundant flora which serves as a repository for researchers in the quest to develop less toxic drugs with little or no side-effect for the management of BPH