Diversity, distribution of the ginger family (Zingiberaceae) in West Sumatra based on herbarium specimens and its potency for genetic resources essential oil

Zingiberaceae is popular plant family that is widely used for medicinal purposes, as cooking spices, and as a source of essential oils. The Zingiberaceae family is characterized by its significant reliance on essential oils. This study aims to inventory, analyze distribution, and review the potential of essential oils from Zingiberaceae species. The species inventory is based on observations of herbarium specimens, and the potential of essential oils is known through a literature review. A total of 2,500 herbarium specimens stored at the Andalas University Herbarium (ANDA) and the Bogoriense Herbarium (BO) were identified. The results showed 100 species belonging to 20 genera of Zingiberaceae in West Sumatra. Zingiberaceae are found administratively in almost all cities and districts in West Sumatra, with Padang City and Mentawai Islands District. Geographically, Zingiberaceae are distributed in secondary and mixed forests in the lowland, medium elevation, and hilly to montane zones. Based on a literature review, 12% of Zingiberaceae species have been commercialized, 24% have potential for essential oil production, and the rest have not been studied for their essential oil content. The main components of essential oils found in Zingiberaceae are monoterpenes and sesquiterpenes.


Introduction
Zingiberaceae (Ginger family) is a tropical and subtropical plant that has 3782 species from 115 genera in the world [1].The distribution center of Zingiberaceae is in Southeast Asia and South Asia, with the richest area in the Malesian region which includes Brunei, Malaysia, Philippines, Singapore and Indonesia [2,3].Sumatra, with 76 species, is one of the distribution centers of Zingiberaceae in Indonesia [4].
The authentic evidence of the existence of Zingiberaceae in Sumatra is in the form of herbarium specimens that have been preserved in nearby herbaria.However, another challenge is that most of the Zingiberaceae specimens are collected by the public, However, most Zingiberaceae specimens are collected by non-experts who do not fully understand how to collect and preserve Zingiberaceae specimens., as also stated by [5].In recent decades, research on the Zingiberaceae family has been actively conducted in Sumatra.Along with the active research on the Zingiberaceae group in Sumatra, we have reorganized the method of collecting Zingiberaceae specimens, and the obtained specimens are stored in the herbarium of Universitas Andalas (ANDA) and the Bogoriense herbarium (BO).Some specimens have been utilized to publish new findings (new records) as well as new species (new species) from Sumatra [6,7,8,9].
The classification and naming of Zingiberaceae taxa have changed as a result of a taxonomic revision study that several researchers have conducted on taxa in the family [10].The revision of the Amomum genus, which has produced several new genera, has increased the number of genera.Therefore, it is necessary to adjust the classification to the latest one.
From the perspective of the utilization of Zingiberaceae by the community, several researchers have actively conducted studies through a local wisdom approach.The findings have indicated that local communities, in addition to cultivating the recognized species, also employ wild species of 1255 (2023) 012030 IOP Publishing doi:10.1088/1755-1315/1255/1/012030 2 Zingiberaceae for traditional medicine and diverse other uses.[11].Even the traditional healers (sikerei) of the Mentawai community in Siberut Island use around 75% of the wild Zingiberaceae species, consisting of 32 types found in Siberut, for traditional medicine [12].Empirical evidence has also been conducted on several species that potentially exhibit beneficial bioactivity.The results have identified eight Zingiberaceae species from West Sumatra that demonstrate antioxidant activity, which is able to bind free radicals [13].Elettariopsis slahmong, a wild Zingiberaceae species from West Sumatra, has been proven to have potential as a biopesticide for black pod disease caused by the fungus Phytophthora palmivora in cocoa plants [14].Another wild species, Zingiber macradenium, which is an endemic species in Sumatra, has been utilized by the local community for toothache medicine.Antibacterial studies have shown that this species has the potential to be an antibacterial agent against the Streptococcus mutans bacteria in teeth [15].
For the study of essential oil content, specific to Zingiberaceae plants in Sumatra, no findings have been found yet.However, information on the essential oil of several species with broader distribution and also found in other areas has been discovered.In terms of utilization, essential oil is one of the common products of Zingiberaceae.The essential oils from the Zingiberaceae family are widely used and traded, especially in foreign markets, such as cardamom, ginger, and turmeric oil.Cardamom oil (Elettaria cardamomum) is widely produced in Sri Lanka and India, as is ginger oil (Zingiber officinale), which is mainly produced in China and India [16].
The essential oils of Zingiberaceae are reported to have antioxidant and antibacterial activity, as several Zingiberaceae leaves that have been successfully isolated, including Curcuma aeruginosa, Curcuma domestica, Curcuma zanthorrhiza, Curcuma zedoaria, Elettaria cardamomum and Zingiber officinale are potential essential oils for antioxidants and antiglycation, with the dominant active compounds being caryophyllene [17].
To determine the presence of a Zingiberaceae plant species in a certain area, specimens collected in the herbarium are examined.In this study, an initial observation of Zingiberaceae specimens in the Herbarium of Universitas Andalas and Herbarium Bogoriense was conducted, which resulted in 2,500 sheets of Zingiberaceae specimens in the Sumatra Barat region.The objective of this study is to determine the diversity and distribution of Zingiberaceae species in Sumatra Barat based on the coordinate information available on the herbarium specimen labels and to identify potential Zingiberaceae species that produce essential oil based on a literature review.

Study Area
The study area is limited to the region of West Sumatra.Geographically, West Sumatra province is located between 0 º54' LU dan 3 º30' LS, 98 º36' BT and 101 º53'BT with a land area of 42,297.30km2.West Sumatra is situated along the western coast in the central part of the Sumatra island, encompassing both lowland and volcanic highland areas that have been shaped by the Bukit Barisan mountain range.

Plant materials
This study utilized Zingiberaceae specimen materials collected from the Herbarium Andalas (ANDA) and the Herbarium Bogoriense (BO)

Plant Diversity
This research used the herbarium method with systematic observation of Zingiberaceae specimens stored in the Andalas University herbarium (ANDA).Identification was carried out on each type of Zingiberaceae specimen following [18] by using a determination key, comparing it with descriptions in literature such as Takano (2003), Poulsen (2006), and J. Droop (2014), and comparing it with type specimens obtained from the GBIF, JSTOR, and POWO websites.Scientific names were verified on the WFO Plantlist and POWO websites.Specimens that had been identified were verified by Zingiberaceae experts at Herbarium ANDA, Andalas University

Distribution of Zingiberaceae
The distribution map aims to present information on the distribution of Zingiberaceae species scattered at locations in the Sumatra Barat region.The distribution map was made using the QGIS 3.10.5 application.Administratively, the distribution of Zingiberaceae was obtained from coordinate information on the herbarium specimen labels.Geographically, the distribution of Zingiberaceae was obtained from the altitudinal information listed on each herbarium specimen label.

Potential of Zingiberaceae Essential Oil
The potential data for Zingiberaceae species were obtained from literature reviews by referring to 40 national and international journals, especially in the last 10 years.

Species Diversity of Zingiberaceae in West Sumatra Based on Herbarium Specimens
From 2490 specimens of Zingiberaceae, a total of 100 species from 20 genera were collected and preserved in the Andalas Herbarium.The number of Zingiberaceae species can be seen in Figure 2.

Figure 2. Zingiberaceae species in West Sumatra based on herbarium specimens
Based on observations made on the Andalas herbarium specimens, out of 2490 specimens, 100 species from 20 genera were found in West Sumatra.This number exceeds the previously reported findings by [4], where they found 76 species from 18 genera of Zingiberaceae in Sumatra, particularly in West Sumatra, only 27 species of Zingiberaceae were found.The high number of Zingiberaceae species obtained indicates the high diversity of Zingiberaceae in West Sumatra.This is due to the active research on Zingiberaceae in West Sumatra in recent years [6,7,11].
Referring to genetic diversity, the Zingiberaceae family, comprising 100 species, exhibits a high level of genetic diversity when found within a single population in West Sumatra.In [19] study, which focused on the analysis of genetic diversity and population relationships of Alpinia galanga species using Amplified Polymorphism, a total of 120 individuals from 28 populations were examined.The study revealed a relatively low genetic diversity in A. galanga among the 28 populations.This can be attributed to the evolutionary process and indicates the level of gene flow between populations.
The highest number of species is found in the genera Globba and Hornstedtia.Each genera has 14 species.The genera Globba is the most frequently encountered specimen in the herbarium due to extensive field explorations that collected specimens of this genus.This is related to the genetic diversity of the Globba genera.The high species diversity within the genus Globba indicates a high genetic diversity.In line with [20], it was reported that the analysis of genetic diversity and gene flow among populations of Globba leucantha species is quite restricted, indicating high genetic diversity.This genus has also been previously studied by [6].According to [6], 16 species of Globba were found in Sumatra.This genus is relatively large and dominant in the Sumatra region.According to [21], the genera Globba has a wide distribution range, ranging from the eastern Himalayas and southern China to Malaysia.Almost all species of Globba are found in humid areas, along riverbanks, and in shaded locations.The genera Hornstedtia comprises 14 species found in West Sumatra.The genera Hornstedtia has a significant number of species in the Andalas Herbarium (ANDA).In the analysis of genetic variation in Hornstedtia, the study involved examining the variation and differences in genetic characteristics among species within the genus.This analysis has been previously conducted by [22], who utilized the molecular marker ITS, revealing two distinct groups within Hornstedtia as indicated on the phylogenetic tree of Hornstedtia and resulting in several different variations..The genera Hornstedtia has been studied by [22], who found 13 species in West Sumatra.According to [1], this genus is the largest genus in Sumatra, with a total of 91 species worldwide.The distribution of the Hornstedtia genera is quite extensive in the Malesian region, including the Malay Peninsula, Java, Borneo, Sumatra, Philippines, Sulawesi and New Guinea.
The species with the least presence are found in the Camptandra, Elettariopsis, Sulettaria, and Sundamomum genera.The Camptandra genus has a small and difficult-to-find population.According to [4], there are only four Camptandra species found in the Malaysian region, namely Camptandra gracillima, Camptandra latifolia, Camptandra ovata, and Camptandra parvula.The Sulettaria genera is also found in small numbers, with only 15 Sulettaria species worldwide [1].The Sundamomum and Elettariopsis genera are newly accepted genera that were previously classified under the Amomum genus [23].

The distribution of Zingiberaceae species in West Sumatra based on herbarium specimens
Administratively, Zingiberaceae plants can be found in almost all districts and cities in West Sumatra.Information on the location of Zingiberaceae species can be found based on the location indicated on the label of collected herbarium specimens.The distribution of Zingiberaceae in Sumatra can be observed in the following (Figure 2; Figure 3; Figure 4).
Based on observations made on specimens from the Herbarium Andalas (ANDA), administratively, the most commonly found type of Zingiberaceae in West Sumatra is in the city of Padang and the Mentawai Islands.Geographically, the Padang area and the Mentawai Regency have extensive forest coverage (Figure 2).This is due to the high level of field exploration activities for Zingiberaceae species in the areas.Another estimate is that the geographical conditions in West Sumatra will influence the plant diversity found within it.For example, the Bukit Barisan region, which is part of the Gunung Leuser National Park and the Kerinci Seblat National Park, is known for its fertile land and humid environment, leading to high plant diversity within the area [24] In terms of altitude, Zingiberaceae can be found ranging from 0 to 2200 meters above sea level (Masl).Zingiberaceae can be found in lowland areas, hilly regions, and mountainous areas (Figure 3).According to [25], Zingiberaceae can thrive from lowland areas up to an altitude of 2000 MASL, particularly in areas with high humidity and rainfall.According to [26], tropical forests in lowland vegetation are dominant in some parts of Sumatra.The altitude zones in Sumatra, as described by [26], are divided into seven categories: Lowland vegetation (0-150 Masl), Low elevation hills (150-500 Masl), Medium elevation hills (500-900 Masl), Submontane regions (900-1400 Masl), Lower montane regions (1400-1900 Masl), Montane regions (1900-2500 Masl), and tropical upper montane and subalpine regions, which are mostly above 2500 Masl, including the mountain peaks.
Based on land cover, Zingiberaceae in West Sumatra is predominantly found in areas of secondary dry forests, mixed shrublands, and plantations (Figure 4).According to [9], Zingiberaceae is often found in secondary forests and open habitats, particularly along riverbanks and in humid areas.Indicating a relatively small amount of land conversion and a humid environmental condition, resulting in rich biodiversity within these areas.According to [27] land coverage conditions are closely related to environmental temperature.As land coverage decreases, surface temperature increases, and vice versa, as land coverage becomes denser, surface temperature decreases.

The potential of Zingiberaceae as a producer of essential oil
Out of 100 species of Zingiberaceae, several species were found to have the potential to be producers of essential oils based on literature studies conducted (Table 1).In the research, each species was grouped into three categories, namely potential, commercial, and unexplored (Figure 6).

Figure 6. Categories of Zingiberaceae species that have the potential to produce essential oils
The category labeled as "potency" refers to Zingiberaceae types that possess essential oils and have been the subject of research due to their potential properties..The "Commercial" category refers to essential oil types that have produced products, have been processed, and are traded by the community.Meanwhile, the "Unexplored" category refers to types that have not been studied for their essential oil content; thus, there has been no research or journal publications on the essential oils of these types.
Based on the data obtained, the number of potential Zingiberaceae plant species as essential oil producers is 24 species, with 12 commercial Zingiberaceae plant species and 63 unexplored Zingiberaceae plant species.The Zingiberaceae species that have the potential to produce essential oils have been widely utilized by the local community for medicinal purposes, aromatherapy, and food flavoring The genus Etlingera, specifically the species E. coccinea, E. elatior, E. littoralis, E. maingayi, E. megalocheilos, and E. pyramidosphaera, are dominant among Zingiberaceae species that have the potential to produce essential oils.Several species from the genera Wurfbainia, Hornstedtia, Alpinia, Amomum, Kaempferia, Curcuma, Zingiber, Globba, Hedychium, and Meistera have the potential to produce essential oils but have not been processed into commercial products.However, they have been utilized by local communities, such as the species Etlingera elatior, which has been reported to have antioxidant, antibacterial, anticancer, and cytotoxic activities that have great potential in traditional medicine but need further investigation of their bioactivity [28].
Commercially categorized species, such as several species from the genera Alpinia, Curcuma, Boesenbergia, Zingiber, and Wurfbainia, have been processed and marketed as essential oil products, including A. galanga, A. malaccensis, B.rotunda, C. longa, C. mangga, C. zanthorrhiza, C.zedoaria, K. galanga, W. compacta, Z. cassumunar, Z.officinale, Z. zerumbet. .These species have been extensively processed by communities into natural essential oil products developed for use in medicine and aromatherapy.For example, Zingiber officinale has a high market value due to its various functions in the cosmetics, food, aromatherapy, and pharmaceutical industries [29].The genera Globba and Hornstedtia are dominant in unexplored Zingiberaceae species.After conducting a literature review, it was found that several species in these genera have not been scientifically studied for their essential oil content.This is followed by several species from the genera Meistera, Schapochlamys, and Plagiostachys, which are also included in the unexplored Zingiberaceae species and require further research.

Total Spesies
Based on literature studies, the content of essential oil compounds is varied in terms of quantity and type, and each type has different chemical components.The main components found in Zingiberaceae species are hydrocarbon essential oils, namely terpene, monoterpene, and sesquiterpene components.The essential oil content of Zingiberaceae species in West Sumatra can be seen in Table 1.Octadiene, Zingiber zerumbet (L.) Roscoe ex Sm.
The components of essential oil content have been used in traditional medicine for various health conditions, the development of perfume and cosmetic products, and essential oils are often used in cooking to provide taste, aroma, and health benefits.For example, the turmeric plant (C.longa) is beneficial for treatment due to its antioxidant and anticancer properties.C. longa contains 10% curcumin, 1-5% bisdemethoxycurcumin, essential oil consisting of sesquiterpene ketones, turmerone 60%, zingiberene 25%, phellandrene, sabinene, borneol, and cineole, 3% carbohydrates, 30% protein, 8% starch, 45-55% vitamin C, and mineral salts, iron, phosphorus, and calcium [63].The species C. longa can become a promising export commodity for C. longa business opportunities.This is due to its wide market segment and smooth marketing process, without encountering significant obstacles [64].
Based on the obtained data, there are still many unexplored and unstudied species of Zingiberaceae regarding their essential oil content.There are 64 species that require further research and development to obtain more information about the contained essential oil content.Additionally, there are 24 Zingiberaceae species with potential for containing essential oils that can be utilized in the commercial industry.Furthermore, the productivity of essential oil content and the potential development of superior varieties need to be enhanced for the 12 Zingiberaceae species that have already entered the commercial market, in order to add value to the products.

Table 1 .
Zingiberaceae species with potential for essential oil production in West Sumatra.