Clausena anisum-olens (PROSEA)

Plant Resources of South-East Asia Introduction

List of species

1, branchlet with immature fruits; 2, pistil (var. anisum-olens); 3, calyx and pistil (var. mollis (Merrill) Molino).

Clausena anisum-olens (Blanco) Merrill

Protologue: Bur. Gov. Lab. (Publ.) 17: 21 (1904).

Family: Rutaceae

Chromosome number: 2n= 18

• Cookia anisum-olens Blanco (1837),
• Clausena laxiflora Quis. & Merrill (1928),
• Clausena sanki (Perr.) Molino (1994).

• Philippines: anis, kayumanis (Tagalog), danglais (Bagobo).

C. anisum-olens is endemic to the Philippines and Borneo. In the Philippines it is distributed all over the archipelago and is also cultivated occasionally. It is sporadically cultivated in gardens in China, Taiwan, Vietnam and Indonesia. In China (Guangxi, Guangdong, Yunnan) it seems to occur naturalized as well.

In the Philippines leaves of C. anisum-olens are used as a condiment in preparing local dishes and beverages and to flavour cigarettes. The essential oil from the leaves is a potential substitute of anise oil, e.g. for the preparation of the Philippine drink "Anisado". It is also well known in traditional medicine in the Philippines: the leaves are stuffed into pillows for a soporific effect, they are used in baths against rheumatism, or in decoction for nausea during pregnancy. Cough with fever is treated with a decoction of the roots and fruit.

C. anisum-olens is of local importance only and is not traded internationally. Production and trade statistics are not available.

On steam distillation or alcoholic extraction, the leaves of C. anisum-olens yield 1-3.5% essential oil. The oil is a mobile pale-yellow liquid with an odour similar to that of star-anise oil. The physical characteristics of an oil distilled in Java are: specific gravity (26°C/4°C): 0.96, optical rotation: -0.1, refractive index (30°C): 1.56. The chemical composition of the oil varies among individual plants from almost pure methyl chavicol (estragol) to almost pure anethol. A minor component is anisaldehyde.

• Evergreen shrub or small tree, 2-6(-15) m tall, bearing essential-oil glands on all aerial parts which emit a strong anise or anise-like smell when crushed.
• Leaves alternate, imparipinnately compound, 20-55(-100) cm long, glabrous to villose; petiolules 1-5 mm long; leaflets 7-13(-19), alternate to subopposite, ovate to lanceolate, 3-25 cm × 1-10 cm, the largest ones near the apex, base oblique, margin undulate-crenulate, apex acute-acuminate, densely dotted with pellucid glands.
• Inflorescence a terminal (rarely axillary), conical panicle, 6-40 cm long; pedicel up to 2 mm long.
• Flowers globose in bud, when opened 6-8 mm in diameter, regular, 5-merous, fragrant; calyx 5-lobed, 0.5-1 mm long, green; petals 5, free, ovate-elliptical, 4-5 mm long, membranaceous, whitish-green; stamens 10, free, filaments geniculate, white, anthers yellow; ovary globose to somewhat pentagonal, about 1 mm long and wide, 5-locular, born on gynophore 0.3-0.5 mm long, style 1 mm long, stigma slightly 5-lobed.
• Fruit a globose (rarely ovoid) berry, 0.8-1.6 cm in diameter, whitish-green turning pinkish at maturity, 1(-3)-seeded.
• Seed green.

No data are available on growth and development of C. anisum-olens in its natural habitat. In the Bogor Botanical Garden cultivar Clausanis produced only few viable seeds and seedlings grew slowly, attaining barely 3 m height in 3 years. Better results were obtained when "Clausanis" was grafted on Clausena excavata Burm.f.: in 2 years a height of 4.5 m was reached. C. excavata is widespread in most parts of South-East Asia; it flowers year-round, so seed is always available and seedlings can be grafted when they are 6-12 months old. Healthy plants of C. anisum-olens including those grafted on C. excavata tolerate pollarding fairly well. Weak plants, however, suffer severe setback from low pollarding, especially when cut back to less than 50 cm in height.

C. anisum-olens (Blanco) Merrill is formally invalidated by Clausena sanki (Perr.) Molino (based on Illicium sanki Perr. (1824), a name that antedates the basionym Cookia anisum-olens Blanco of 1837). In order to avoid an unnecessary name change, it has been proposed that Illicium sanki Perr. be rejected, also because it is based on material of 2 different species.

C. anisum-olens is subdivided into 3 botanical varieties:

• var. anisum-olens : distributed as the species, except Borneo; whole plant subglabrous; leaves up to 50 cm long with 7-13(-15) leaflets; fruit globose, up to 1 cm in diameter;

• var. calciphila (B.C. Stone) Molino: synonym: C. calciphila B.C. Stone; occurring in Borneo (Sarawak and Kalimantan); whole plant subglabrous; leaves up to 1 m long with 11-19 leaflets; fruit ovoid, 1.5-1.6 cm × 1-1.1 cm;

• var. mollis (Merrill) Molino: synonym: C. mollis Merrill; occurring in the Philippines (Luzon, Mindanao); almost whole plant densely golden-yellow pilose; leaves with 11-15(-19) leaflets.

All information about uses and essential oil content refer to var. anisum-olens only. Data on cultivation refer to only a single cultivar of this variety: "Clausanis". "Clausanis" developed from plants collected in the Philippines in 1820 that were subsequently taken to Réunion Island and Paris. From Réunion a few plants were taken to the Botanical Garden in Bogor. There, through cultivation and successive self-pollination it developed its typical character: a very short and asymmetrical style, an unusual feature in Clausena Burm.f. "Clausanis" has been cultivated and studied from 1905 onwards in Bogor as C. anisata. However, C. anisata (Willd.) Hook.f. ex Benth. (synonyms: C. dentata (Willd.) M. Roemer, C. dunniana A. Léveillé) is a related, but completely different species occurring in tropical and southern Africa, southern India and from Bangladesh to southern China and Thailand. It has only axillary inflorescences. Its leaves yield an essential oil very rich in anethol and similar to the oil of C. anisum-olens.

C. anisum-olens grows naturally in the understorey of rainforest, on various soil types (including limestone), up to 1500 m altitude. In cultivation in Indonesia it only performed well up to 500 m altitude. In Solok (west-central Sumatra) it grows well with 2000 mm annual rainfall with maxima in March and November and a minimum of about 75 mm per month from June to August, with maximum temperatures of about 30°C and minima of about 20°C throughout the year, and on poor, acid (pH 4.0-4.2) soils.

"Clausanis" produces very little seed and is propagated vegetatively. Grafting "Clausanis" on a rootstock of C. excavata is the easiest and most efficient way of propagation. Other rutaceous rootstocks (Citrus spp., × Citrofortunella spp.) have also been tested, but gave poorer results. Propagation by cuttings proved to be very difficult, as it requires constant high temperatures (above 23-25°C) and adequate soil moisture. Budding onto C. excavata has given poor results. In vitro propagation of "Clausanis" has also been tested in Bogor, with promising preliminary results.

In Solok, densities of 10 000-15 000 plants/ha have given good results; earlier about 3000 plants/ha had been recommended in Java.

In Solok, plants of "Clausanis" grafted on C. excavata are pruned back to a height of about 1 m once or twice a year after harvest. If this pruning process starts early, it leads to the formation of a flat-topped, sometimes bushy shrub, from which leaves can be picked easily from above (as in tea plantations).

At high planting densities, all leaves of C. anisum-olens above 0.8-1 m can be plucked 2-4 times per year. Trees should be maintained at about 1 m height by means of post-harvest prunings. Frequency and timing of harvests should be guided by the rate of regrowth and depend on the availability of water. When water and nutrient requirements are met, leaf production is highest under unshaded conditions. The first harvest can be 1 year after grafting on 2-4-year-old rootstocks.

The first year, a single harvest amounts to 0.6-1 kg leaves per tree. In the second year 1.7-2.2 kg are collected in two harvests. In subsequent years a tree yields 2.5-4 kg leaves annually, independent of the frequency of harvesting.

After harvesting the leaves it is recommended to extract the oil as soon as possible. Fermentation of the leaves should absolutely be avoided because it leads to production of unpleasant notes in the essential oil. If necessary, it is possible to store the leaves for 2-3 days in a properly ventilated room where they may slightly dry without fermentation. A too strong desiccation would lead to a severe loss of the oil by evaporation, either directly through the thin walls of the pellucid glands or by crumbling them during handling of the fragile dried leaves. Essential oil is mostly extracted from the leaves by steam distillation. Distillation for 4-5 hours in a still with a 120 kg capacity yields more than 90% of the total essential-oil content. Prolonged distillation would negatively affect the quality of the oil. Oil yield is 1.6-2 kg oil from 100 kg fresh leaves. Preliminary estimates for production of essential oil per ha suggest that yields of 350-750 kg per year may be possible.

Little is known about wild representatives of C. anisum-olens from the Philippines. They may be more vigorous, have a higher growth rate, produce more seed and have a higher essential-oil content than "Clausanis", and could be used for breeding and genetic improvement. However, no germplasm collections or breeding programmes are known to exist.

The essential oil from the leaves of C. anisum-olens has potential use as a cheap source of natural anethol. It could compete not only with star-anise and anise oils in food, beverage and pharmaceutical industries, but also with semi-synthetic anethol, a by-product of the turpentine-oil industry in the United States, in soaps, detergents and cosmetics.

• Brown, W.H., 1941 (reprint 1954). Useful plants of the Philippines. Vol. 2. Department of Agriculture and Natural Resources. Technical Bulletin 10. Bureau of Printing, Manila, the Philippines. pp. 227-231.
• Molino, J.-F., 1993. History and botany of Clausena anisum-olens (Blanco) Merr. Cv. "Clausanis" (Rutaceae), a promising essential oil crop plant. Acta Horticulturae 331: 183-190.
• Molino, J.-F., 1994. Révision du genre Clausena Burm.f. (Rutaceae) [Revision of the genus Clausena Burm.f. (Rutaceae)]. Bulletin du Muséum National d'Histoire Naturelle, Section B, Adansonia 16: 105-153.
• Molino, J.-F, 1995. Proposal to reject Illicium san-ki Perr., a threat to Clausena anisum-olens (Blanco) Merr. (Rutaceae). Taxon 44: 427-428.
• Quisumbing, E., 1951. Medicinal plants of the Philippines. Katha Publishing Co., Manila, the Philippines. pp. 456-457.
• Toxopeus, H.J., 1950. Clausena anisata. In: van Hall, C.J.J. & van de Koppel, C. (Editors): De landbouw in de Indische Archipel [Agriculture in the Indonesian Archipelago]. Vol. 3. W. van Hoeve, the Hague, the Netherlands. pp. 719-722.
• Wiersum, L.K., 1949. Enige gegevens voor een mogelijke cultuur van Clausena [Some data on a possible cultivation of Clausena]. Landbouw (Buitenzorg) 21(9): 445-455.

Clausena anisum-olens: Brown, W.H., 1921 (reprint 1953). Minor products of Philippine forests. Vol. 2. Department of Agriculture and Natural Resources, Bureau of Forestry, Bulletin No 22. Bureau of Printing, Manila, the Philippines. Fig. 71, p. 215 (fruiting branch); Molino, J.-F., 1994. Révision du genre Clausena Burm.f. (Rutaceae) [Revision of the genus Clausena (Rutaceae)]. Bulletin du Muséum National d'Histoire Naturelle, section B, Adansonia 16. Fig. 6, p. 139 (pistils). Redrawn and adapted by P. Verheij-Hayes.

J.-F. Molino