diversifolia (Hemsl.) A. Gray, belonging to the Asteraceae family, commonly known as Mexican sunflower, produces essential oils that spread worldwide. This species is native to Mexico and Central America and is a weed that spreads in various ecosystems, especially in Africa and China. The results of Sampaio and Da Costa’s research showed that there are different chemotypes for T. diversifolia species according to the samples’ geographical origin. Differences in the accumulation of ß-pinene in essential oils and variations in the production of certain classes of secondary metabolites, such as terpenes, seem to respond to different abiotic environmental conditions directly. This study also shows that tissue-specific changes that produce secondary metabolism are adaptive strategies for different environments [32].
1.2.2.3 Harvesting
Determination of harvest time is critical to get quality raw materials. Post-harvest processes such as processing into dry raw materials, transportation, and storage must also be carried out at optimal conditions to produce the reproducible quality of raw materials. The primary source of medicinal plants comes from the wild, so that exploitation can cause natural damage and extinction of some species. Plant collected from the wild have problems regarding the homogeneity of the quality. The agroclimatic conditions will affect the chemical composition and therapeutic properties. One medicinal plant widely used in India, Terminalia chebula, originates from India’s various parts, known to have different therapeutic properties [33].
Harvest time will affect the composition of the chemical content in plants. Therefore the harvest must be done at the right time. It is known that the chemical content of plants is directly correlated to the stage of plant development. In Ayurveda, Andrographis paniculata (Kalmegh) is used as a hepatoprotective. A study conducted by Pandey and Mandal revealed that the maximum andrographolide levels (2.85%) were found at the initiation of flowering or harvested after 130–150 planting days. The highest level of Rauwolfia serpentine root alkaloid is at the age of 18 months. The plant maturation stage at the root of Wihania somnifera (Ashwagandha) is 130–180 days after planting, while the peak maturity of Tinospora cordifolia (Giloe) stems is 15 months. In Ayurvedha, Adhatoda vasica (Adusa or Vasaca), used as a bronchodilator, contains vasicine on its leaves. This plant blooms in March (fully bloomed) and September (partially blooms). At the flowering stage, these compounds’ levels were 3.0 and 1.4% in March and September, respectively. Whereas at the vegetative stage, the vasicine levels are very low [33].
Lemongrass oil, obtained from (Cymbopogon citratus), is one of the essential oils widely used in the perfume, cosmetic, beverage, and pharmaceutical industries as aromatic and antiseptic. Citral content is a characteristic of lemongrass oil quality. There are 65 compounds in lemongrass oil, but only 13 compounds are always present in the lemongrass oil harvested at different ages. Citral levels are also different when lemongrass is harvested at different maturity stages. Optimal citral content in lemongrass oil is obtained when harvested at the age of 6.5 and 7.0 months [34, 35].
Artemisia annua L. (Asteraceae) which has antimalarial activity, is a commercial antimalarial compound source. Essential oils of A. annua are used in the perfume and cosmetics industries. In the essential oil is found main compounds such as camphor, artemisia ketone, germacrene D, and 1,8-cineole. The variability of the chemical composition of essential oils of A. annus depends on the geographical origin and stage of plant development. Before the flowering stage, the essential oil content was 0.8%, then increased rapidly to 1.38% after the flowering stage. The main compounds (artemisia ketone, camphor, and 1,8-cineole) and the highest antioxidant activity in essential oils are taken at the full flowering stage [36].
Adulteration that occurs is often done for profit. Adulteration is done by adding foreign material, which is usually cheaper and dangerous. Illicium verum Hook. F., which is used as a drug for infant colic, is often counterfeited or mixed with I. anisatum. I. anisatum contains neacoxic sesquiterpene dilactone anisatin, a strong non-competitive GABA antagonist. Both have morphological similarities. This adulteration case causes many cases of adverse neurological reactions such as nausea, hallucinations, and epileptic seizures, especially in small infants [11].
Another example of adulteration occurs in Saffron (dry red stigmata Crocus sativus L.), one of the expensive raw materials. Saffron is often added with other similar ingredients, reducing therapeutic efficacy. Other raw materials such as ginseng are often diluted with cheap fake ingredients Platycodon grandiflorus (Jacq.) A. DC. or with different ginseng species, such as P. quinquefolius L. (American ginseng), P. ginseng C.A. Meyer (Asian ginseng), or P. notoginseng. There is a problem with this mixing. Different ginseng species have different saponin profiles, thus giving different pharmacological effects. American ginseng and Asian ginseng have been reported to have contradictory effects on the vascular system and blood glucose levels [11].
1.2.2.4 Post-Harvesting Process
Water is a component that determines the physical and chemical properties of plant constituents. Decreasing plants’ moisture content by the drying process, intended to prevent the activity of enzymes and microbes, extends shelf life. Dry raw materials simplify the process of transportation and storage. Many factors affect the drying method. Therefore a drying method must be chosen that does not change or reduce the phytochemical content [11, 37].
Camellia sinensis or C. assamica is the most popular drink in the world whose use can be in the form of green, black, or oolong. Green tea has important and extensive pharmacological activities. But to maintain its quality, the drying method is very limited due to the instability of its chemical content. Chemical ingredients in green tea are vitamins, chlorophyll, flavonoids, dan polyphenols, which have antioxidant activity [38].
The drying process affects the recovery of taxol from Taxus baccata. Yield taxol from the stem is not affected by drying temperature, while the yield of taxol from leaves will increase with increasing drying temperature. Drying at low temperatures will produce a low yield because it requires a longer drying time so that the enzyme activity causes taxol to degrade [37].
1.2.2.5 Storage
After post-harvesting, medicinal plants often have to be stored long enough before being used as raw materials for various products. For this reason, the storage method must be suitable so that it does not cause physical, chemical, and microbiological changes. Storage is intended to ensure that there is no loss of quality. Some methods are used to control humidity and air movement to prevent metabolic activities, which can damage the content of compounds in it. Another way is to prevent attacks by insects, mice, and microorganisms [39, 40].
Echinacea purpurea (Asteraceae) is a medicinal plant with immunostimulatory and anti-inflammatory activities, especially in alleviating cold symptoms. The storage process affects alkamide and cichoric acid content in E. purpurea root, in reverse. Alkamide levels did not change when stored for 60 days in the dark at 50 °C, while cichoric acid levels reduced by 70%. On storage in light at 200 °C, the cichoric acid level did not change, while the alkamide level dropped by 65%. Temperature and light affect the compound content of E. purpurea [39, 41].
The composition of the chemical content of essential oils from aerial parts of Thymus daenensis Celak did not show changes during storage in the freezer (−20 °C). Storage at room temperature (25 °C) also does not reduce its quality because there is an increase in the levels of thymol and carvacrol. The storage temperature affects the composition of the compounds in the essential oil of Hyptis pectinata L. Poit. Compared with storage in the freezer, storage at room temperature showed increased levels of β-elements, α-copaene, germacrene D, and caryophyllene compounds. Oxide and (E, E)-α-farnesene and decreased α-humulene and β-caryophyllene [40].
Changes
